Topic: Reliability of sites such as mempool.space for estimating fees. - page 2. (Read 376 times)

There are currently over 440,000 transactions with the least priority (which pay 1-6 sat/vb), so don't enter a fee rate of that range, as they're probably there for days. Click on the most left block from mempool.space to see yourself what fits your need best.

For example, paying something like 7.1 sat/vb can get you confirmed in a couple of hours in the worst case.

What? First time hearing a bad experience with mempool.space. They're like the most favorite block explorer. Tells you exactly what you need to know, and the styling rocks. What hot and cold colors? Why should high fees be red flag if there aren't overpaying?

The issue at the moment, which has been the case for a few weeks, is that there is a huge backlog of transactions paying 6 sats/vbyte waiting to be confirmed, with the volume above that spread very thinly. So it is entirely possible that 8 sats/vbyte would put you within 0.1 MvB of the tip of the mempool, 7 sats/vbyte would put you 1-2 MvB from the tip, while 6 sats/vbyte puts you anywhere from 2-30 MvB from the tip. So you pick low priority at 6 sats/vbyte, and then a few blocks are found in quick succession and your transaction is mined. That's not a failure of mempool.space, but rather a quirk of state of the current mempool.

Bear in mind of course that transactions don't pay either 6 or 7 sats/vbyte, and there is a continuous range between these two numbers which most fee estimators will not pay attention to. 6.0 sats/vbyte and 6.9 sats/vbyte will be a difference of over 25 MvB from the tip at the moment.

Having said that, mempool.space is currently stating the "No Priority" fee is 14 sats/vbyte, which is only 2.5 MvB from the tip. That's not "No Priority" in my book. If I had a "No Priority" transaction, I'd set it to around 6.8 sats/vbyte and expect it to be confirmed sometime in the next 24 hours.

So yeah, as others have said, take a look at Jochen Hoenicke's site instead. Not only can you place your transaction exactly as far from the tip as you want, but more importantly you can view the current mempool trends and see if it is filling up or emptying out.

Yes, I knew that. The point is that I had previously been guided by mempool.space and found it to be approximately reliable. It has been the last few times that I have had the impression that it was giving estimates that were too high.


I guess with the time I've been using bitcoin, it's about time I used something more sophisticated, like this website. It's not the first time I've visited it, I guess I've seen it mentioned on the forum, bud you have to do the calculations yourself instead of being guided by the simplest thing, which is that a website gives you the estimated fees for a quick confirmation.

I understand that I can take this as a general rule? 1vMB from the top for a confirmation of a few hours and a few more sats for faster confirmations.


Yes, that's for sure.

I prefer to use Jochen-hoenicke.de website when I need to check mempools too.

Two reasons why I dislike mempool.space website.

• It is very bad designed, bad organized in fee rate bands' colors. Their color bands are mixing from hot to cold colors that is annoying already. Moreover, they use hot colors at bottom and cold at top. We know, most expensive fee rates are considered as 'dead' ones. They should use hot colors like red flags. I don't get ideas why mempool.space team designed like that or perhaps they see low fee rates as red flags.
• In the past, their chart is static, not dynamic. Static means when I hover a mouse on their chart, fee rates won't be updated. It is not dynamic like Jochen-hoenicke.de website. Recent months (around 2021 or 2022), they updated their chart to be a dynamic one but I still dislike it because of color bands.
  
  • Static chart: https://web.archive.org/web/20210811200553/https://mempool.space/graphs#24h
  • Dynamic chart: https://web.archive.org/web/20220823122230/https://mempool.space/graphs/mempool

Well, "estimates" are just estimation based from statistics and shouldn't be relied on with 100% accuracy.
The longer your projection is (like 48hours), the harder it is to make a close estimate since nodes' mempools states in the future cannot be predicted.

As for mempool.space, it seems like they have their own fee rate estimation using their own API  (e.g.: mempool.space/api/v1/fees/recommended)
Based from the result of the above, it's not similar to Bitcoin Core's estimatesmartfee or estimaterawfee.
For accuracy, there's no way to tell or rather, fee estimation algorithms aren't really meant to be accurate, those are just trying to suggest the "best" fee rate for your target block.

Here's the source code of their fees API, BTW: https://github.com/mempool/mempool/blob/master/backend/src/api/fee-api.ts

I prefer to use Johoe's Bitcoin Mempool Site Statistics, which quickly shows how fees developed in the past 24 hours. It shows there was a bump in fees yesterday, and if you would have made a 6.x sat/vbyte transaction at that point, it would have taken 10 hours to confirm. You couldn't predict that bump in fees before it happened.

Correct. I like to put it this way: the recommended fee is an estimate based on past transactions and blocks, while your new transaction depends on other transactions made and blocks found in the future. It's an estimate, that's it.

For having a good estimation, the best thing you can do is to check and analyze the mempool by yourself. To do so, you can use jochen-hoenicke website.
At the time I am writing this post, mempool.space is suggesting the fee rate of 11 sat/vbyte for high priority and 9 sat/vbyte for low priority. If you check jochen-hoenicke website, you will see that you can put your transaction at 1 vMB from the tip with only 7 sat/vbyte.

If I want to make a transaction now and I want it to be confirmed very fast, I would set the fee rate to around 10 sat/vbyte.
If I can wait for a few hours, 7 sat/vbyte is more than enough.

Mempool congestion is not constant. It can drop and it can increase. If the mempool congestion drops, the fee rate and the fee required to get high priority confirmation will be reduced. If the mempool is becoming more congested, the fee rate and the fee required to get high priority confirmation will be increasing.

It depends on how mempool is. But right now, the purging is at 5.96 sat/vbute (not constant either). Any transaction with fee rate that is less than 5.96 sat/vbyte will not be successfully broadcasted right now.

I had usually relied on mempool.space to guide me on what fee to use to send my transactions but lately it seems to give me too high a fee. I remember a couple of times recently when I wasn't in a hurry to get a transaction confirmed and if the site gave high priority 8 sat/vB, medium priority 7 sat/vB and low priority 6 sat/vB, I sent it with 6 sat/vB and it was confirmed in a few blocks. I didn't check exactly but I would say it was confirmed in three or four blocks at most, in less than an hour for sure. Then, the last time I sent a transaction I still sent it with a lower fee, if it gave me low priority 10 sat/vB and 9 sat/vB as no priority, I sent it with 9 and it also confirmed relatively quickly.

I don't know if you have had this impression recently with mempool.space or the sites you use.

The thing is that I could send it with an extremely low fee and then raise it with RBF but if I am not in a hurry to get a transaction confirmed but I would like it to be confirmed within 48 hours maximum, if mempool.space marks 9 sat/vB as no priority it seems silly to send the transaction at 2, for example, because I will have to end up bumping the fee for sure and I don't think it's worth the hassle to save a few satoshis.