Ancestor Fee Rate Mining — Glossary

TERM_DEF // TRANSACTION / ANCESTOR_FEE_RATE_MINING

ANCESTOR FEE
RATE MINING

mining/">Ancestor Fee Rate Mining. A miner selection algorithm that picks transactions by their full ancestor-set feerate, not just their own.

This page sits in the Transaction section — How money moves: inputs, outputs, fees, signatures, sighash flags, and the formats that wrap them. Read on for what it is, why it exists, how it works under the hood, and what to watch out for.

WHAT_ANCESTOR_FEE_RATE_MINING_IS

Ancestor Fee Rate Mining — at a glance

TRANSACTION

Ancestor Fee Rate Mining is part of the FEE ECONOMY sub-family of transaction-level concepts. Fee paid per virtual byte of transaction size (sat/vB) — the actual price miners use to rank txs for inclusion. A miner selection algorithm that picks transactions by their full ancestor-set feerate, not just their own.

Why it exists

DESIGN

Bitcoin's block-space auction has limited supply (~1.7M vbytes per block) and unlimited demand. Sorting by absolute fee would unfairly favour large transactions; sorting by feerate prices each byte fairly.

HOW_IT_WORKS

Mechanism

HOW IT WORKS

feerate = fee_sats / virtual_size_vbytes. Miners build blocks by sorting mempool by feerate descending and packing until full. The "next block" feerate at any moment is the boundary value — pay above it for fast confirmation.

1. Wallet selects UTXOs whose total value covers the spend amount + estimated fee (coin selection). 2. Wallet builds the transaction body: version, inputs (each with prev txid + vout + sequence), outputs (each with value + scriptPubKey), locktime. 3. Wallet computes the sighash for each input (which parts of the tx the signature commits to — controlled by the SIGHASH flag). 4. Wallet signs each input with the right private key. Witness/scriptSig is populated with the resulting signatures + pubkeys. 5. Tx is broadcast to peers. Mempool propagation: tens of seconds globally. 6. A miner includes it in a block. Confirmation count grows by 1 per block; after ~6 the tx is effectively final.

WORKED_EXAMPLE

Ancestor Fee Rate Mining — FEE ECONOMY

EXAMPLE

Example tx size fee feerate small P2WPKH transfer 140 vB 2,800 20 sat/vB multisig redemption 250 vB 5,000 20 sat/vB large CoinJoin (10 hops) 1,500 vB 45,000 30 sat/vB Mempool view : mempool.space, mempool.observer, bitcoin-cli getmempoolinfo Fee estimator : bitcoin-cli estimatesmartfee 6 → feerate for ~6 block confirm

KEY_PROPERTIES

PER-VBYTE

Miners rank by sat/vB, not absolute fee. A 2,000-vbyte tx paying 20,000 sats (10 sat/vB) loses to a 200-vbyte tx paying 6,000 sats (30 sat/vB).

ATOMIC

A transaction is either fully accepted into a block or fully rejected. There is no partial spend.

IMMUTABLE INPUTS

A UTXO can only ever be spent once. After that, it is permanently consumed.

NO BALANCES

Bitcoin tracks UTXOs, not balances. Your wallet computes a balance by summing the UTXOs it controls.

COMMON_PITFALLS

Things that catch people out

PITFALLS

address-reuse/">Address reuse degrades privacy — every reuse links more of your UTXOs together publicly. Modern wallets generate a fresh address per receive.
Fee estimation matters: under-pay and your tx sits in the mempool for hours; over-pay and you tip the miner more than necessary. Use a fee estimator.
"Change outputs" must go back to a fresh address you control. A missing output/">change output sends the difference to the miner as fee — a known footgun.
RBF (Replace-By-Fee) lets you re-broadcast a tx with a higher fee. Useful for stuck txs but means a 0-confirmation tx is never truly final.

RELATED_CONCEPTS

Other terms from Transaction — click any to read its page:

TERMINOLOGY_INDEX

TERMINOLOGY

Ancestor Fee Rate Mining

A miner selection algorithm that picks transactions by their full ancestor-set feerate, not just their own.

Transaction (Tx)

A signed payload spending one or more UTXOs and creating new ones; every state change in Bitcoin is a tx.

Raw Transaction

The hex-serialized bytes of a transaction, ready to broadcast or analyze.

Transaction ID (TXID)

HASH256 of a transaction's pre-witness serialization; used to reference outputs by (txid, vout).

wTXID (Witness TXID)

HASH256 of the full transaction including witness data; commits to signatures and used in the witness commitment.

Input

A reference to a previous output being spent, plus the data (scriptSig/witness) authorizing the spend.

Output

An (amount, scriptPubKey) pair created by a transaction; spendable later by a tx whose input references it.

UTXO (Unspent Transaction Output)

An output that hasn't been spent yet; your "balance" is the sum of UTXOs you can sign for.