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Topic: Report: Prices of Mining One Bitcoin Worldwide (Read 297 times)

legendary
Activity: 1610
Merit: 1026
September 06, 2023, 06:31:37 PM
#27

If you're looking for cheap places to mine one BTC then Lebanon (266.02inUSD), Iran(532.04), and Syria ($1,330.10) might be your best bet but keep in mind that these countries lack reliability and consistency when it comes to power input which means setting up a mining farm there might not be very practical after all!
The latest news about Syria speaks of military operations in the territory of this country, and other countries do not look like a good place for mining due to bans and military conflicts. Iran also has a military conflict with Israel. Therefore, in practice, large mining companies will not build data centers there.
newbie
Activity: 7
Merit: 0
It's important to take into account that these calculations were based on several factors such as eight different ways people mine Bitcoin (each with its own hash rate) and a mining difficulty of 53,911,173,001,055.00 as a benchmark (which gets adjusted precisely every 2,016 blocks). Furthermore, while these countries offer low electricity costs for mining 1BTC it doesn't necessarily mean they are reliable or consistent sources of power input for setting up mining farms. This is why many countries have actually banned Bitcoin from being mined or traded within their borders due to concerns over energy consumption and lack of regulation on cryptocurrencies in general.

If you're looking for cheap places to mine one BTC then Lebanon (266.02inUSD), Iran(532.04), and Syria ($1,330.10) might be your best bet but keep in mind that these countries lack reliability and consistency when it comes to power input which means setting up a mining farm there might not be very practical after all!
legendary
Activity: 2170
Merit: 6279
be constructive or S.T.F.U
10. Bhutan - $4,256.33

Few months back there was an article on Bhutan on how the Kingdom has been secretly mining Bitcoin using natural resources. When they are mining using green energy why would they need to spend money on electricity. I am not sure why was Bhutan mentioned in this article. If the King is mining will he allow his citizens to venture into this direction. I do not think so.

Not speaking for the idiots who wrote the article, but green energy is not free.

1- You have to calculate the investment involved.
2- The lost opportunity of selling the power to someone else.

So if you can sell the power you generate of a river flowing or sun shining on your solar panels for $10,000 a year, then that is your electricity cost.
hero member
Activity: 2100
Merit: 771
Top Crypto Casino
10. Bhutan - $4,256.33

Few months back there was an article on Bhutan on how the Kingdom has been secretly mining Bitcoin using natural resources. When they are mining using green energy why would they need to spend money on electricity. I am not sure why was Bhutan mentioned in this article. If the King is mining will he allow his citizens to venture into this direction. I do not think so.
legendary
Activity: 2828
Merit: 6108
Jambler.io
... and after taking a closer look at some of the outrageously incorrect numbers stated ...
...
And the most unprofitable countries to mine 1 BTC are:
1. Italy - $208,560.33
2. Austria - $184,352.44
3. Belgium - $172,381.50
4. Denmark - $166,795.06
...
#2 is Australia, not Austria - say sorry to everyone in that country for mistyping the name ...
and somehow, magically it costs 3.68 times more in Australia than in New Zealand right next to Australia Smiley

The one painting the map was the one that made the mistake, the prices in their math, as stated in the methodology are influenced by this: https://www.globalpetrolprices.com/electricity_prices/
And the most expensive places are, in reverse order Germany,Denmark,Belgium,Austria,Italy.
The weird thing is that he has mistaken Austria for Australia but was able to put New Zealand on a map, usually, lazy people simply forget about it. Looking at Australia at 0.231 it should be like 20% more expensive than New Zealand at 0.183 and 3 times cheaper than Italy.

One more thing would be why is Poland green and Romania magenta when Romania has cheaper electricity according to the same source, but like who really cares about those details when the whole thing is just stupid.


legendary
Activity: 4466
Merit: 1798
Linux since 1997 RedHat 4
... and after taking a closer look at some of the outrageously incorrect numbers stated ...

...
And the most unprofitable countries to mine 1 BTC are:
1. Italy - $208,560.33
2. Austria - $184,352.44
3. Belgium - $172,381.50
4. Denmark - $166,795.06
...

#2 is Australia, not Austria - say sorry to everyone in that country for mistyping the name ...

and somehow, magically it costs 3.68 times more in Australia than in New Zealand right next to Australia Smiley
legendary
Activity: 1610
Merit: 1026
Experts say: 21-31 thousand dollars
kano says: that the calculations are not reliable in the long run, even for several months
Experts answer that kano is not an expert Smiley

These experts have never been involved in mining, and do not understand the risks and possible additional costs.
legendary
Activity: 2170
Merit: 6279
be constructive or S.T.F.U
Just for fun and for the sake of proving that this study is complete b.s, I will take the fist country on the list "Lebanon" which according to the study it costs only 266$ to mine a whole bitcoin.

It costs 10c USD per kWh for the first 100kWh and then 27c / kWh so it costs $71,639 (using the most efficient gear out there as Kano pointed out above) to mine a single bitcoin and not 266$ , obviously I used 27c and not 10c because regardless of which miner you use, you will go past the first tier of 100kWh in no time every month, so you might save a few hundred dollars during the first tier, so that 71k might be 70k or slightly below, but ya, still way too far from being just 266$.

It's also worth meeting that Lebanon generates around 500MW ONLY, while the minimum demand there is 3500MW, so the average city gets electricity only for 4 hours ( could be more or less depending on the demand which is mainly determined by the season), so basically, you can't even mine BTC in Lebanon using the grid, let alone do that with 266$, I think they got that number by visiting some "English speaking" website that has little to no info of what has been going on in Lebanon for the past a few decades, and they use the electricity price that was valid 30-40 years ago and then they reflect it on today's data, the end result obviously is complete rubbish.

I know for sure the numbers are 100% wrong for Syria, Sudan, and Libya as well, I am also willing to bet it's wrong for the rest of the countries they labeled as (cheapest to mine BTC), so I won't even bother to research those, I 'l just stick to the claim that "they are all wrong" and wait for someone else to prove otherwise.
legendary
Activity: 4466
Merit: 1798
Linux since 1997 RedHat 4
Lulz - it's all complete crap.
N00b thread wanting people to post - thus why he hasn't replied.

So, here's a simple way to work it out (hopefully I've made no mistakes)

The 'expected' hashes to mine a block, at the moment right now, before the next diff change,
is of course called the network difficulty.

So what is it?, simple, currently 55.6T
Which is ... 55.6x10^12 Diff
1 diff = 2^32 Hashes
1 Block = 6.25 BTC

So the hashes you 'expect' to do per BTC is 55.6x10^12 x 2^32 / 6.25

Now to pull a 'reasonable' number out of the air, 25J/T - most home miners will be worse than this, few will be better than it.

So the 'expected' W/hr to mine 1 BTC, this week, at 25J/T is 2^32 * 55.6 * 25J / 3600s / 6.25 = 265.33MWHr

If electricity is (high) 10c, that'll cost $26533 at 25J/T

If electricity is (fucking low) 1c, that'll cost $2653 at 25J/T


Now, since I've done all this tapping away on my laptop, not at home, and not able to easily get at info, anyone feel free to point out any mistakes I've made Wink

Edit: and in case it wasn't clear at the start, this depends directly on the network difficulty, which changes about every 2 weeks,
so any long term attempt at estimating it will be very wrong, even a short estimate of a few months will be noticeably wrong, after the fact, also.
legendary
Activity: 2226
Merit: 1172
Privacy Servers. Since 2009.
So, I stumbled upon this CoinGecko article titled "Household Electricity Costs to Mine 1 Bitcoin at Home, Around the World" (https://www.coingecko.com/research/publications/bitcoin-mining-cost), and honestly, I was pretty intrigued by it. They've got this report that lists which countries make mining 1 Bitcoin super profitable and which ones, well, not so much.

Without further ado, the top 10 countries for profitable Bitcoin mining are:
1. Lebanon - $266.02 (electricity cost to mine 1 BTC in USD)
2. Iran - $532.04
3. Syria - $1,330.1
4. Ethiopia - $1,596.12
5. Sudan - $2,128.17
6. Libya - $2,660.21
7. Kyrgyzstan - $2,660.21
8. Angola - $3,724.29
9. Zimbabwe - $3,990.31
10. Bhutan - $4,256.33

And the most unprofitable countries to mine 1 BTC are:
1. Italy - $208,560.33
2. Austria - $184,352.44
3. Belgium - $172,381.50
4. Denmark - $166,795.06
5. Germany - $163,336.79
6. Ireland - $159,612.50
7. Lithuania - $152,163.92
8. Netherlands - $137,798.79
9. United Kingdom - $130,616.23
10. Cayman Islands - $128,222.04

Here's a nice graphic.



They did some pretty serious calculations to figure out how much electricity it takes to mine a single Bitcoin. They considered eight different ways people mine, each with its own hash rate, and then they looked at how long it usually takes to mine one Bitcoin using each method. They used a mining difficulty of 53,911,173,001,055.00 as a benchmark. By the way, this mining difficulty thing gets adjusted precisely every 2,016 blocks, and how often it changes depends on how many people are mining and how powerful their computers are. They used CoinWarz Bitcoin calculator to keep tabs on all that. Check out the article for more info.

Very nice compilation. $266.02 is dirt cheap for 1 BTC. However, you need to take into account crime rates, corruption etc which can affect the final price. But of course, taking everything into account, electricity price in Italy is hard to beat...  Grin
legendary
Activity: 1610
Merit: 1026
According to their calculation method, the ASIC, depending on the hashrate, produces a block in solo in 1340-3900 days, and the ASIC with the largest hashrate has the highest probability. But I don’t know how this system takes into account the future increase in complexity and the emergence of new ASICs every year. Asik will die earlier, so it is difficult to verify these calculations.

Lol did they really say that? As of today, the most powerful asic miner needs 20 years to mine a single block, and this assumes no change in difficulty in neither direction.

Simply put, the whole study is a waste of energy, probably more people will read it than this topic, but ya, that is the reason why most people are ignorant.
This same study is done by experts!!
Look at the table and ask yourself why the cost of mining 1 bitcoin in solo is indicated? After all, there are at least 7 bitcoins in one block, taking into account the block reward and commissions, and to get 1 bitcoin, you need to mine the whole block.
Therefore, I am sure that any ASIC will be broken earlier, the experiment is impossible Smiley
legendary
Activity: 4116
Merit: 7849
'The right to privacy matters'
because you need to use 1eh  not 100th

1000000 x 0.00000221 = 2.21 btc a day at viabtc which is a block in just under 3 days. or 6.63 btc in 3 full days

No variance no diff adjustment

power cost for that at 5 cents is about $11.25 for each 100th machine you use.

You need 10,000 machines  for 1 Eh

10,000 x 11.25 = 112500 usd for 6.63 btc = 16,968 usd a coin.


but  
zero cost to buy the 10,000 machines
zero cost for the wires
zero cost for the building
zero cost for labor
zero cost for theft




and that is a shit ton of money.


Even if you give the caveat that

the power cost for a coin is 17,000 if you have 5 cents power and have  payment for the machines  is achieved

you are still saying that for 10,000 machine you have

1)zero cost for maintenance and repair
2)zero cost for the wires
3)zero cost for the building
4)zero cost for labor
5)zero cost for theft
6)zero cost for cooling and filters

to get that 17,000 a coin cost.

I could venture a guess at what it cost for that list but even at 25 cents a machine it is 2500

so 17000+2500= 19500 a coin for a 5 cent power guy assuming the has fully paid off the gear is close.

Since the began 6 cents or less has worked

if you are a six cent guy

20,400 is power cost + 2500 = 22,900 a coin. so six cent power and 30 watt a th gear is on the line of breakeven.

As I think my 2500 extra cost number is too low as most are paying off the gear which is likely 5000 more to the numbers

so a six cent guy is 20,400+2,500+5,000 = 27,900 or break even or  tiny loss.

very tight for a 6 cent guy
not that good for a 5 cent guy
 4 cent looks okay

13,600+2500+5000 = 21100
legendary
Activity: 2170
Merit: 6279
be constructive or S.T.F.U
According to their calculation method, the ASIC, depending on the hashrate, produces a block in solo in 1340-3900 days, and the ASIC with the largest hashrate has the highest probability. But I don’t know how this system takes into account the future increase in complexity and the emergence of new ASICs every year. Asik will die earlier, so it is difficult to verify these calculations.

Lol did they really say that? As of today, the most powerful asic miner needs 20 years to mine a single block, and this assumes no change in difficulty in neither direction.

Simply put, the whole study is a waste of energy, probably more people will read it than this topic, but ya, that is the reason why most people are ignorant.
legendary
Activity: 1610
Merit: 1026
They did some pretty serious calculations to figure out how much electricity it takes to mine a single Bitcoin.

It's more so they did some pretty stupid calculations to come up with this rubbish, there is no way on planet earth you can mine a whole BTC at your house, sure not in any of those countries they listed as "cheap", the single new gen miner consumes 3kw which is probably more than a few hours max capacity in most of the countries listed, so you can't even plug that shit at home.

If you are lucky, the average gear you can run at an average home in one of those countries would be an S9 that does 14th, and that would require 440 years to mine a single bitcoin assuming difficulty stays flat and no halvings, so you looking at a few centuries to mine a single bitcoin, so in a life time, all those houses that may mine bitcoin combined won't mine what a single large miner in the U.S can mine in a day, so what is the purpose of this study?

Also, how did they get the electricity rate for those countries? probably via a Google search, because I can assure you at least half of those figures are incorrect, most countries with cheap electricity have tier-based costs, and that tier-based cost will ramp up in a few days after running a small miner like an S9, Let alone an S19 or M30s.
According to their calculation method, the ASIC, depending on the hashrate, produces a block in solo in 1340-3900 days, and the ASIC with the largest hashrate has the highest probability. But I don’t know how this system takes into account the future increase in complexity and the emergence of new ASICs every year. Asik will die earlier, so it is difficult to verify these calculations.
legendary
Activity: 2170
Merit: 6279
be constructive or S.T.F.U
They did some pretty serious calculations to figure out how much electricity it takes to mine a single Bitcoin.

It's more so they did some pretty stupid calculations to come up with this rubbish, there is no way on planet earth you can mine a whole BTC at your house, sure not in any of those countries they listed as "cheap", the single new gen miner consumes 3kw which is probably more than a few hours max capacity in most of the countries listed, so you can't even plug that shit at home.

If you are lucky, the average gear you can run at an average home in one of those countries would be an S9 that does 14th, and that would require 440 years to mine a single bitcoin assuming difficulty stays flat and no halvings, so you looking at a few centuries to mine a single bitcoin, so in a life time, all those houses that may mine bitcoin combined won't mine what a single large miner in the U.S can mine in a day, so what is the purpose of this study?

Also, how did they get the electricity rate for those countries? probably via a Google search, because I can assure you at least half of those figures are incorrect, most countries with cheap electricity have tier-based costs, and that tier-based cost will ramp up in a few days after running a small miner like an S9, Let alone an S19 or M30s.
newbie
Activity: 3
Merit: 0
For example, in Laos, the government recently ordered to stop mining. At first, I thought that the measures taken to limit the production of cryptocurrencies for reasons of excessive consumption of electricity or the prevention of illegal mining, but in the end everything turned out to be simpler. Mining companies have large debts for electricity and the government has decided to sell excess electricity to neighboring countries.
wait why don't they just sell the surplus minerals
legendary
Activity: 1708
Merit: 1615
#SWGT CERTIK Audited
For example, in Laos, the government recently ordered to stop mining. At first, I thought that the measures taken to limit the production of cryptocurrencies for reasons of excessive consumption of electricity or the prevention of illegal mining, but in the end everything turned out to be simpler. Mining companies have large debts for electricity and the government has decided to sell excess electricity to neighboring countries.
legendary
Activity: 1610
Merit: 1026
This means in the years to come this is gonna be problem. Since electricity cost is rising but block reward is decreasing.

There are also other factors to consider, which are alternative energy sources, bitcoin prices, and technological advancement. That being said, the market will always balance itself. Even in the current market people keep mining Bitcoin and increasing its difficulty even though the profit is likely small. At the very least this goes to show that some of them are betting that their earned rewards will be worth more in the future.
Russia has a developed energy infrastructure, but already industrial miners are facing problems of lack of electricity. And in other countries, too, there are restrictions on consumption. Consumption in Russia at the end of the year by industrial miners alone could rise to 2.5 GW. Further, it will take 1-2 years to develop the infrastructure.
legendary
Activity: 2170
Merit: 1789
This means in the years to come this is gonna be problem. Since electricity cost is rising but block reward is decreasing.

There are also other factors to consider, which are alternative energy sources, bitcoin prices, and technological advancement. That being said, the market will always balance itself. Even in the current market people keep mining Bitcoin and increasing its difficulty even though the profit is likely small. At the very least this goes to show that some of them are betting that their earned rewards will be worth more in the future.
legendary
Activity: 1610
Merit: 1026
In many countries there is still a lot of cheap hydro, atom, solar electricity, so miners will look for more favorable conditions for installing mining equipment. The volume of purchased electricity is also very important, because the prices in the wholesale markets do not increase as much as the tariffs for small customers.
full member
Activity: 1092
Merit: 227
This is not real right? We have already long gone from the days when we used to be lucky enough to mine one bitcoin just like that. I hardly think any miner will stumble upon a Bitcoin on solo mining trip. I don't really believe that. Moreover there is less chance due to another fact and that's ever increasing cost of everything from the mining equipment, the maintainance, electricity is but obvious and moreover high price volatility. You never know how Bitcoin price might surprise you if it falls.  Roll Eyes

For example, the electricity cost in US. If you check the actual price then it is always higher in terms of inflation and needs to be adjusted. For every 4-5 years there is a cent raise in actual while more than 4-5 cent raise in the inflation value. This means in the years to come this is gonna be problem. Since electricity cost is rising but block reward is decreasing.

legendary
Activity: 2828
Merit: 6108
Jambler.io
So, I stumbled upon this CoinGecko article titled "Household Electricity Costs to Mine 1 Bitcoin at Home, Around the World" (https://www.coingecko.com/research/publications/bitcoin-mining-cost), and honestly, I was pretty intrigued by it.

No reason to be intrigued it's the same thing as discussed a year ago
https://bitcointalksearch.org/topic/--5405856
and it's just a bit of BS moving two values in an excel sheet as many miners have pointed out.

They take the average electricity price and draw calculations, forgetting one important thing, no miner mines at average prices!
And I have to add, no miner mines at consumer price either as they would simply go bankrupt.

If you look strictly at that map you see Mexico scoring twice as cheap as the US, but there are no major farms in Mexico while at least 40% of the hash rate is in the US, and the reason is simply, while that index price has the US at:

Quote
USA electricity prices
Household, kWh   Business, kWh
 U.S. Dollar   0.174   0.146
Riot does so at 2.5 cents:
https://www.sec.gov/Archives/edgar/data/1167419/000107997321000537/ex99x1.htm

700% is quite a stretch, isn't it?



legendary
Activity: 4214
Merit: 4458
Another factor is their source of electricity. If it is the national grid the rates are as I said before, otherwise they could use renewable energies, start their own power plant in which case they'd receive super cheap gas which can be as low as $0.0008, or participate in the building of new power plants using the gas flares to produce electricity and get it practically for free. Although this last one was just a news I once read, I don't know if the project was started or not.

starting own power plant.. yes the fuel is cheap but the conversion to electric is not
same as gas flaring. it seems like free energy but then you have to include the equipment to turn burned gas into electric. also flared gas pipes only release a certain amount of dirty gas which is not enough to power a whale asic farm per flare pipe
the trials of 'flare-mining' is small scale mining per site (less than a shipping container per pipe)

much like this topics failure.. it fails to include the device/equipment and maintenance cost.. which is why it does not actually cost $266 to mine bitcoin in lebanon
legendary
Activity: 1568
Merit: 6660
bitcoincleanup.com / bitmixlist.org
Without further ado, the top 10 countries for profitable Bitcoin mining are:
1. Lebanon - $266.02 (electricity cost to mine 1 BTC in USD)
2. Iran - $532.04
3. Syria - $1,330.1
4. Ethiopia - $1,596.12
5. Sudan - $2,128.17
6. Libya - $2,660.21
7. Kyrgyzstan - $2,660.21
8. Angola - $3,724.29
9. Zimbabwe - $3,990.31
10. Bhutan - $4,256.33

I dunno, you better have some backup generators available if you are mining in these areas, since the electricity is unpredictable and can usually gets knocked out for long periods of time.

Also like pooya87 said, these prices don't take into account extra requirements and regulations for businesses. You can't just start a mining farm in these places and connect it to the grid, you have to explain why you are using so much electricity.
legendary
Activity: 3444
Merit: 10537
Household Electricity Costs to Mine 1 Bitcoin at Home
~
2. Iran - $532.04
This is inaccurate. The price of electricity for homes in Iran is about $0.001 per kilowatt hour but that's for the home users and the KWH they'll use. A miner uses more electricity which means the rate will enter an automatic step-by-step price scheme where each time the usage surpasses the next step's threshold the price increases. I believe the ceiling is $0.03 per KWH though.

Additionally big miners have to follow the regulations which have changed a couple of times over the past couple of years. Basically in these contracts they receive special rates for their farms which depends on a bunch of factors. For example it depends on the month, during the peak usages in summer their rate is equal to the export rate which I think is less than 5 cents; and in the rest of the year the rate is half that.
Another factor is their source of electricity. If it is the national grid the rates are as I said before, otherwise they could use renewable energies, start their own power plant in which case they'd receive super cheap gas which can be as low as $0.0008, or participate in the building of new power plants using the gas flares to produce electricity and get it practically for free. Although this last one was just a news I once read, I don't know if the project was started or not.
legendary
Activity: 4214
Merit: 4458
using difficulty is a little bit of a guess.. as is playing around with the different asics and also doing it based on solo mining which without guessing the difficulty of the next 7 years. you cant actually guess the cost of solo mining over seven years

a better method is to look at the average network hashrate of a 2 week point..
then simply divide that down by the average asic speed of current gen asics. to see the average number of asics running

then knowing how many asics are probably mining at any time they can look the cost per bitcoin of the network (as solo mining is a whole different ball game)



EG their list of asics                                   Thash  KWH    hash/KWH
Bitmain Antminer S19 XP Hyd (255Th)        255     5.3      48.11320755
Bitmain Antminer S19 XP (140Th)              140     3.01     46.51162791
Bitmain AntMiner S19 Pro+ Hydro              198     5.45     36.33027523
Canaan Avalon Miner A1366                       130    3.25     40
Canaan Avalon Miner A1346                       110    3.3       33.33333333
MicroBT WhatsMiner M53S++                    320     7.04     45.45454545
MicroBT WhatsMiner M53                           226    6.55     34.50381679
MicroBT WhatsMiner M33S++                    220    6.82     32.25806452
                                      average hash/kwh = 40 TH/kw (rounded)

average hashrate=400exa
=10000000KWH used
with 6 blocks an hour and 6.25btc a block = 266667KWH /btc

after doing these calculations this way. you wil find the article also done them this way to calculate the network rate.. because with Lebanon's $0.001 electric price also equals $266(excluding hardware and labour cost of maintaining)

however the article falsely pretends it calculated it based on difficulty and by pretending its the solo cost over 7 years.. (which they didnt factor in the 7 years of possible difficulty changes they would assume to have calculated if they were doing a properjob under their mentioned method)
member
Activity: 98
Merit: 10
shop.sesterce.com
So, I stumbled upon this CoinGecko article titled "Household Electricity Costs to Mine 1 Bitcoin at Home, Around the World" (https://www.coingecko.com/research/publications/bitcoin-mining-cost), and honestly, I was pretty intrigued by it. They've got this report that lists which countries make mining 1 Bitcoin super profitable and which ones, well, not so much.

Without further ado, the top 10 countries for profitable Bitcoin mining are:
1. Lebanon - $266.02 (electricity cost to mine 1 BTC in USD)
2. Iran - $532.04
3. Syria - $1,330.1
4. Ethiopia - $1,596.12
5. Sudan - $2,128.17
6. Libya - $2,660.21
7. Kyrgyzstan - $2,660.21
8. Angola - $3,724.29
9. Zimbabwe - $3,990.31
10. Bhutan - $4,256.33

And the most unprofitable countries to mine 1 BTC are:
1. Italy - $208,560.33
2. Austria - $184,352.44
3. Belgium - $172,381.50
4. Denmark - $166,795.06
5. Germany - $163,336.79
6. Ireland - $159,612.50
7. Lithuania - $152,163.92
8. Netherlands - $137,798.79
9. United Kingdom - $130,616.23
10. Cayman Islands - $128,222.04

Here's a nice graphic.



They did some pretty serious calculations to figure out how much electricity it takes to mine a single Bitcoin. They considered eight different ways people mine, each with its own hash rate, and then they looked at how long it usually takes to mine one Bitcoin using each method. They used a mining difficulty of 53,911,173,001,055.00 as a benchmark. By the way, this mining difficulty thing gets adjusted precisely every 2,016 blocks, and how often it changes depends on how many people are mining and how powerful their computers are. They used CoinWarz Bitcoin calculator to keep tabs on all that. Check out the article for more info.
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