Maybe it is the pool that some of you are doing your estimates that are lower than mine; I am with CKPool.
Kano.is CKPool
Mar 2016, 129 Blocks, 4.16 Blks/Day
Apr 2016, 134 Blocks, 4.47 Blks/Day
May 2016, 126 Blocks, 4.07 Blks/Day
Jun 2016, 132 Blocks, 4.40 Blks/Day
4.275 average per day (based upon the last 4 months)
Today July 4th 2016 my pool (CKPool) hit 4 blocks (we still may hit more). My total Payout was $277.37. $277.37 x 30 days per month = $8321.10. Halving it would be $4160.55
If you would like to do the numbers with the average per day 4.275: $277.37/4=$69.34 per block; $69.34 x 4.275 ave per day = $296.43 ave per day; $296.43 * 30 days per month = $8892.90 ave per month; After halving $4445.
I still do not see the $800 - $1000 estimate per month that you are talking about. Another factor is the increase in Bitcoin over the next six months that would negate or at least mitigate the difficulty. Maybe you are just wanting see the price reduced?
Topic: FOR SALE - BTC MINING FARM - 30 S7s Hosted and In Location. $13,500.00 - page 2. (Read 2021 times)
July 04, 2016, 05:40:38 PM
July 04, 2016, 02:50:26 PM
This seems like a pretty high price for used s7. The monthly profit after halving would be about $3350 at the current price and then minus your hosting cost of $2480 per month.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
Here are the EXACT numbers that I redid for the past month:
Before Halving:
Monthly Gross = $9,747.00 Annual Gross = $116,964
Monthly Net = $7,267.00 Annual Net = $87,8204
After Halving:
Monthly Gross = $4,873.50 Annual Gross = $58,482
Monthly Net = $2,393.50 Annual Net = $28,722.
Exact Payments per month:
14 Miners and 14 PSUs = $80 x 14 = $1,120.00 Colocation and Maint Costs
16 Miners and 16 Rented PSUs ($5 each) = $85 x 16 = $1,360 Colocation and Maint Costs
Total Cost for 30 Miners, 14 owned PSUs and 16 Rented PSUs = $2,480.00
Profits per month = $4,873.50
Colo and Maint per mo = $2,480.00
Net = $2,393.50
Based on the BTC not increasing and the difficulty not changing. Bitcoin and Difficulty will change.
If you lower the price below $6000 I would be interested. A 6 month payoff would be fair to anyone buying this. Other than that you might just keep it and ride it out. Then sell the units on eBay or something. My calculations have this netting anywhere from 800-1000 per month for the next 6 months if everything stays steady, which it might not.
July 04, 2016, 09:11:55 AM
Here are the EXACT numbers that I redid for the past month:
After Halving:
Monthly Gross = $4,873.50 Annual Gross = $58,482
Monthly Net = $2,393.50 Annual Net = $28,722
Your calc is waaay wrong. How do you get $4873.50 per month after halfing with 141th?
It is $3,504 per month (without difficulty increases) for 141TH after the halving.
Right now 1TH makes .0024 BTC per day. After halving 1TH will make .0012 BTC per day.
141TH X .0012 X 30.5 = 5.16BTC per month or $3,504.
July 04, 2016, 07:17:02 AM
Here are the EXACT numbers that I redid for the past month:
After Halving:
Monthly Gross = $4,873.50 Annual Gross = $58,482
Monthly Net = $2,393.50 Annual Net = $28,722
Your calc is waaay wrong. How do you get $4873.50 per month after halfing with 141th?
July 04, 2016, 06:33:13 AM
This seems like a pretty high price for used s7. The monthly profit after halving would be about $3350 at the current price and then minus your hosting cost of $2480 per month.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
Here are the EXACT numbers that I redid for the past month:
Before Halving:
Monthly Gross = $9,747.00 Annual Gross = $116,964
Monthly Net = $7,267.00 Annual Net = $87,8204
After Halving:
Monthly Gross = $4,873.50 Annual Gross = $58,482
Monthly Net = $2,393.50 Annual Net = $28,722.
Exact Payments per month:
14 Miners and 14 PSUs = $80 x 14 = $1,120.00 Colocation and Maint Costs
16 Miners and 16 Rented PSUs ($5 each) = $85 x 16 = $1,360 Colocation and Maint Costs
Total Cost for 30 Miners, 14 owned PSUs and 16 Rented PSUs = $2,480.00
Profits per month = $4,873.50
Colo and Maint per mo = $2,480.00
Net = $2,393.50
Based on the BTC not increasing and the difficulty not changing. Bitcoin and Difficulty will change.
July 03, 2016, 10:11:29 PM
This is a little risky as it would require trust from 2 parties, one of which (NOT you) can up and leave without any real repercussions - if I understand the OP correctly.
I've been thinking about cloud mining/hosted mining, but this has been a major hurdle for me.
I've been thinking about cloud mining/hosted mining, but this has been a major hurdle for me.
July 03, 2016, 09:44:12 PM
This seems like a pretty high price for used s7. The monthly profit after halving would be about $3350 at the current price and then minus your hosting cost of $2480 per month.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
Net profit of: $870
I think the only way you are going to sell this is to sell at about $6000. Even that might be too much. Or you could just ride it out and reap the profit until it's time to shut them off.
July 03, 2016, 01:50:38 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
There may be a little wiggle room, but not much. I do still see a nice profit now and in the next year. Let's take for example 10% difficulty over the next 6 months. That would be compounded, but just for simplicity we will call it 60% increase in difficulty. Then we take the Bitcoin rate at let say double. That is 200% in Bitcoin profitability...leaving a nice margin for profit.
I understand your thinking but you have to consider opportunity cost when mining. If i was to spend $17k on gear and you believe that btc will double in 6 months why wouldnt i just buy btc and end up with $34k after 6 months. Thats why i dont consider the cost of btc price increases, maybe im wrong. Not trying to derail you im genuinely interested i just cant come close to $17k. Let me know if/when you want to reduce the price and we can chat. Thanks and good luck with your sale. It is nice gear.
Edit: where is it being hosted?
Haha, I have a good friend that says the same thing, that he will just invest. His investment last year is at $218 per Bitcoin was a smart investment looking at it now when Bitcoin is at $700. I have congratulated him on his smart investment and showed him how I doubled his profitability over the last year by mining. I made the profit all the way through and have machines that will still make me money.
I cannot give out the name of the hosting agency except when I give the person the phone number to call him to arrange the deal.
The only way mining is more profitable than investing is if the miner returns more BTC than it costs. If the miner doesn't return equivalent or more BTC than it costs, then it is mathematically impossible to yield higher profits than just investing. If a miner costs 8 BTC and creates 6 BTC regardless of the value of BTC so you have less money. Investors have 8 coins, you have 6.
Can these 30 miners create more BTC than what you're charging? Sure, it would require difficulty to stagnate. That would likely occur during a long lasting price slump.
July 03, 2016, 07:44:13 AM
Sorry but unless you do a BIG drop in price you're going to be stuck with this past the halfing in a few days.
I am not in a hurry to sell them. They are and will be profitable past halving.
For you, yes..
July 03, 2016, 07:38:15 AM
Sorry but unless you do a BIG drop in price you're going to be stuck with this past the halfing in a few days.
I am not in a hurry to sell them. They are and will be profitable past halving.
July 03, 2016, 07:19:11 AM
Sorry but unless you do a BIG drop in price you're going to be stuck with this past the halfing in a few days.
July 03, 2016, 06:15:05 AM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
There may be a little wiggle room, but not much. I do still see a nice profit now and in the next year. Let's take for example 10% difficulty over the next 6 months. That would be compounded, but just for simplicity we will call it 60% increase in difficulty. Then we take the Bitcoin rate at let say double. That is 200% in Bitcoin profitability...leaving a nice margin for profit.
I understand your thinking but you have to consider opportunity cost when mining. If i was to spend $17k on gear and you believe that btc will double in 6 months why wouldnt i just buy btc and end up with $34k after 6 months. Thats why i dont consider the cost of btc price increases, maybe im wrong. Not trying to derail you im genuinely interested i just cant come close to $17k. Let me know if/when you want to reduce the price and we can chat. Thanks and good luck with your sale. It is nice gear.
Edit: where is it being hosted?
Haha, I have a good friend that says the same thing, that he will just invest. His investment last year is at $218 per Bitcoin was a smart investment looking at it now when Bitcoin is at $700. I have congratulated him on his smart investment and showed him how I doubled his profitability over the last year by mining. I made the profit all the way through and have machines that will still make me money.
I cannot give out the name of the hosting agency except when I give the person the phone number to call him to arrange the deal.
New Price - $16,000 - no shipping costs, no waiting, full control and profit immediately - This is a GREAT DEAL! 30 Miners and 14 PSUs Already Hosted!
July 02, 2016, 10:44:39 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
There may be a little wiggle room, but not much. I do still see a nice profit now and in the next year. Let's take for example 10% difficulty over the next 6 months. That would be compounded, but just for simplicity we will call it 60% increase in difficulty. Then we take the Bitcoin rate at let say double. That is 200% in Bitcoin profitability...leaving a nice margin for profit.
I understand your thinking but you have to consider opportunity cost when mining. If i was to spend $17k on gear and you believe that btc will double in 6 months why wouldnt i just buy btc and end up with $34k after 6 months. Thats why i dont consider the cost of btc price increases, maybe im wrong. Not trying to derail you im genuinely interested i just cant come close to $17k. Let me know if/when you want to reduce the price and we can chat. Thanks and good luck with your sale. It is nice gear.
Edit: where is it being hosted?
Haha, I have a good friend that says the same thing, that he will just invest. His investment last year is at $218 per Bitcoin was a smart investment looking at it now when Bitcoin is at $700. I have congratulated him on his smart investment and showed him how I doubled his profitability over the last year by mining. I made the profit all the way through and have machines that will still make me money.
I cannot give out the name of the hosting agency except when I give the person the phone number to call him to arrange the deal.
July 02, 2016, 02:33:38 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
There may be a little wiggle room, but not much. I do still see a nice profit now and in the next year. Let's take for example 10% difficulty over the next 6 months. That would be compounded, but just for simplicity we will call it 60% increase in difficulty. Then we take the Bitcoin rate at let say double. That is 200% in Bitcoin profitability...leaving a nice margin for profit.
I understand your thinking but you have to consider opportunity cost when mining. If i was to spend $17k on gear and you believe that btc will double in 6 months why wouldnt i just buy btc and end up with $34k after 6 months. Thats why i dont consider the cost of btc price increases, maybe im wrong. Not trying to derail you im genuinely interested i just cant come close to $17k. Let me know if/when you want to reduce the price and we can chat. Thanks and good luck with your sale. It is nice gear.
Edit: where is it being hosted?
July 02, 2016, 01:11:09 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
There may be a little wiggle room, but not much. I do still see a nice profit now and in the next year. Let's take for example 10% difficulty over the next 6 months. That would be compounded, but just for simplicity we will call it 60% increase in difficulty. Then we take the Bitcoin rate at let say double. That is 200% in Bitcoin profitability...leaving a nice margin for profit.
July 02, 2016, 01:04:26 PM
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
Statistically speaking my guess would be that we shouldn't see the average difficulty rise at a faster rate than my 10% estimate, and I wouldn't be surprised to see it less by years end... Keep in mind that each progressive increase means that it takes more and more machines to make an equivalent increase. Each new hardware platform is yielding less and less incremental improvement, so we'll be close to the point where it probably won't be faster hardware that pushes difficulty, but larger new deployments that do.
Now, if BTC goes to $3k by the end of the year, then people will be spinning up machines like crazy and difficulty could skyrocket, but I really doubt that's realistic - I'd be happy if we saw it at a stable 2x of today (~$1.4k) by December.
July 02, 2016, 12:41:03 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
I am interested too. Not at $17k, and if you are banking on $3k/btc at the end of the year for negotiations that will be tough. Its possible but you need to consider todays rate. If you see $3k prices at the end of the year you can pretty much expect difficulty to rise faster then the current rate as well. Whats your wiggle toom from $17k?
July 01, 2016, 09:52:13 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
Your figures are correct as well as your estimates as long as Bitcoin does not rise at all over the next 7 months. I believe that there is going to be a dramatic increase in BTC due to supply and demand over the next 6 months. My estimates are $1800 in Sept and $3000 by the end of the year.
July 01, 2016, 09:26:48 PM
You can only make profit after you get your money back from this sales. My guess is that there won't be any profit at all after halving.
I am not in a hurry to sell them. After Halving there is still plenty of profit. Just look at the numbers right now: I am making about $9.50 per day per miner = 9.50 x 30 = $285 per month per miner - $80 collocation and maintenance fee = $205 profit per month per miner. Total for 30 miners is $6150.00 per month!
Not too bad. If there is no increase in BTC, after halving this will be $3075 per month. That would be a $36,900 per year profit!
Before Halving:
Monthly Gross = $8,550. Annual Gross = $102,600
Monthly Net = $6,150. Annual Net = $73,800
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,795. Annual Net = $21,540. ---THESE ARE CORRECTED
Exact Payments per month:
14 Miners and 14 PSUs = $80 x 14 = $1,120.00 Colocation and Maint Costs
16 Miners and 16 Rented PSUs ($5 each) = $85 x 16 = $1,360 Colocation and Maint Costs
Total Cost for 30 Miners, 14 owned PSUs and 16 Rented PSUs = $2,480.00
Profits per month = $4,275.00
Colo and Maint per mo = $2,480.00
Net = $1795.00
You should not "guess" when it comes to your income.
These are all assumptions based on the BTC not increasing and the difficulty not changing. MarkAz has estimated the difficulty at 10% which may very well be correct, but the assumption would then be that BTC would increase as he has also eluded. Thanks MarkAz.
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
No, just $80 per machine and then I own 14 PSUs so, I rent PSUs for the other 16 Miners at $5 each per month.
July 01, 2016, 05:12:12 PM
I thought you were paying $80 per miner plus $80 for the PSU's. Wouldn't that be $2480 for costs?
Your costs don't halve after the halving.
Your costs don't halve after the halving.
The difference between his pre-halving gross and net is $2400, so pretty much what you thought... And you're 100% right about his costs not halving, so really it would be more like:
After Halving:
Monthly Gross = $4,275. Annual Gross = $51,300
Monthly Net = $1,875. Annual Net = $22,500
And this doesn't take into consideration that the difficulty has been increasing by about 10% each month (so just subtract 10% from gross):
Net: $1875, $1447, $1062, $716, $404, $124, -$128
So after 6 months, you'll probably be negative mining - of course this assumes that difficulty keeps rising at a constant 10%, and the value of bitcoin basically doesn't increase at all from what it is today. While I believe that the difficulty is probably a good estimate, I'm also a believer that the value of BTC will increase over time.
So 6 months it would net ~$5628, pretty close to the $6750 you've offered, so I imagine you used similar math to come up with that price.
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