# Fees and the mempool

Where a transaction waits before it is mined, how its fee is quoted in sat/vB, and what Blockspace Holdings' own node and fee estimates read.

URL: https://blockspace.wiki/basics/fees-and-the-mempool/

A transaction is not mined the moment it is sent. It waits in the [mempool](https://blockspace.wiki/glossary/mempool/), "the waiting room of unconfirmed transactions that miners choose from", in the words of the Scribbit glossary. Blocks have capacity limits, and Blockspace Value Theory notes that transactions "must compete for inclusion"; the fee is the bid. Once a [block](https://blockspace.wiki/glossary/block/) includes it, it has its first [confirmation](https://blockspace.wiki/glossary/confirmation/).

## How a fee is quoted

A fee is paid in sats, but it is compared as a [fee rate](https://blockspace.wiki/glossary/fee-rate/): sats per virtual byte, sat/vB. block.space's data-types reference gives what a rate buys. At f sat/vB:

- a base byte costs f sats;
- a [witness](https://blockspace.wiki/glossary/witness/) byte costs f/4 sats.

So the same fee rate buys four times as many witness bytes as base bytes. See [vbytes](/basics/vbytes/) and [the witness discount](/basics/the-witness-discount/). The fuller treatment, including how [BTI](https://blockspace.wiki/glossary/bti/) divides a fee among the tokens a transaction was bought for, is on [fee rate](/concepts/fee-rate/).

Blockspace Value Theory describes the time before a block as the phase of "bids for inclusion": transactions broadcast, "producers watching the fee market, bidders guessing at inclusion". It records the fee environment of early to mid 2026 as "sustained periods at 0.13–0.14 sat/vB, with AntPool accepting sub-1 sat/vB inscriptions". *BVT is a living document and an untested thesis.*

## What Blockspace Holdings' node keeps

Which transactions a node keeps in its mempool is relay policy, not consensus. [Blockspace Holdings' own Bitcoin node](https://blockspace.wiki/glossary/blockspace-holdings-node-and-indexers/) reads (as of block 972,320, 2026-10-20 12:17:53 UTC):

| setting | value |
|---|---|
| node | /Satoshi:28.2.0/ |
| fee floor (minrelaytxfee) | 0 sat/vB |
| incrementalrelayfee | 1 sat/vB |
| maxmempool | 300 MB |
| full-RBF | on |

With a floor of 0 the node keeps transactions paying below 1 sat/vB, which blockspacelabs.com calls "the default floor of Bitcoin Core". Its page, read at 2026-10-20 09:07:08 UTC (block 972,298), showed 38,991 transactions in the mempool, 23.7 vMB, of which 38,265 paid below 1 sat/vB. See [sub-1 sat/vB relay](https://blockspace.wiki/glossary/sub-1-sat-vb-relay/) and [relay policy](/concepts/relay-policy/).

## A fee estimate

Scribbit reads fee estimates from explore.block.space, the mempool explorer on Blockspace Holdings' own node. At 2026-10-20 09:36:44 UTC it gave, in sat/vB: economy 1, within the hour 1, fastest 2, and a median of 1.03 for the next block.

## Fees over the whole chain

The census has counted 30,078,484,994,465 sats paid in fees across 1,464,231,426 transactions (as of block 972,318, 2026-10-20 12:15:32 UTC).

Sources:

- block.space docs: data types · https://block.space/docs/datatypes
- block.space docs: Blockspace Value Theory · https://block.space/docs/bvt
- Blockspace Holdings records
- The blockspacelabs.com page (index.html) · https://blockspacelabs.com
- Blockspace Labs facts (data/facts.json) · https://blockspacelabs.com
- block.space meter and summary APIs · https://block.space/api/summary

Live figures: census as of block 972,318, 2026-10-20 12:15:32 UTC; relay as of block 972,320, 2026-10-20 12:17:53 UTC

Updated: 2026-10-20