estimatesmartfee differs a lot on testnet4

External question — Bitcoin Stack Exchange Author: Vojta Myslivec Original post: https://bitcoin.stackexchange.com/questions/130671 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I have two testnet4 nodes, both running Bitcoin Core v30.2 and I use estimatesmartfee API calls to guess fees on the network. I have noticed over time that the estimates vary widely on both nodes and sometimes also by the conf_target . Is there any possibility to make this estimate more reliable? E.g. it currently return on node01 : $ bitcoin-cli estimatesmartfee 3 economical { "feerate": 0.00000974, "blocks": 3 } $ bitcoin-cli estimatesmartfee 10 economical { "feerate": 0.00100314, "blocks": 10 } $ bitcoin-cli estimatesmartfee 50 economical { "feerate": 0.00000988, "blocks": 50 } (please note that the conf_target: 10 has larger fee than for conf_target: 3 ). and on node02 : $ bitcoin-cli estimatesmartfee 3 economical { "feerate": 0.00100369, "blocks": 3 } $ bitcoin-cli estimatesmartfee 10 economical { "feerate": 0.00063429, "blocks": 10 } $ bitcoin-cli estimatesmartfee 50 economical { "feerate": 0.00063429, "blocks": 50 }

External answer — Bitcoin Stack Exchange Author: Abubakar Sadiq Ismail Original post: https://bitcoin.stackexchange.com/a/130716 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. Yes I have noticed this issue independently a while ago. Note that is documented in estimatesmartfee that “In in rare edge cases, monotonically increasing estimates may not be guaranteed. Specifically, given two targets N and M, where M > N, if a sub-estimate for target N fails to return a valid fee rate, while target M has valid fee rate for that sub-estimate, target M may result in a higher fee rate estimate than target N. See: https://github.com/bitcoin/bitcoin/issues/11800#issuecomment-349697807 “