# Bitcoin fee rates: sat/vB versus the total fee

A Bitcoin fee rate measures fee paid per unit of transaction size, commonly satoshis per virtual byte. The total fee is the difference between input and output values. An estimated fee rate can inform a target, but it does not guarantee inclusion within a particular number of blocks.

Evidence: [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/); [Bitcoin Developer Guide: Transactions](https://developer.bitcoin.org/devguide/transactions.html); [Segregated Witness consensus layer](https://raw.githubusercontent.com/bitcoin/bips/927b6de9915c9262615a6399de51b200f81e5aa4/bip-0141.mediawiki)

Canonical: https://degreesofsatoshi.com/encyclopedia/bitcoin-fee-rate/
Published: 2026-10-02
Substantively modified: 2026-10-02
Independently verified by an automated reviewer: 2026-10-02T18:15:23.891Z
Data current through: 2026-10-02

AI-assisted research and drafting with a separate automated source-verification pass; no external expert or named human review is implied.

## Key facts

- **Total fee:** Total input value minus total output value. ([Bitcoin Developer Guide: Transactions](https://developer.bitcoin.org/devguide/transactions.html))
- **Rate:** Total fee in satoshis divided by virtual size gives sat/vB. ([Segregated Witness consensus layer](https://raw.githubusercontent.com/bitcoin/bips/927b6de9915c9262615a6399de51b200f81e5aa4/bip-0141.mediawiki); [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/))
- **Units:** 1 BTC per 1,000 vbytes equals 100,000 sat/vB. ([walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/))

## A small calculation prevents a large unit mistake

An illustrative 200-vbyte transaction at 8 sat/vB targets 1,600 satoshis in fees. The same rate on a 400-vbyte transaction targets 3,200 satoshis. The rate is equal; the total cost is not.

Conversely, paying 2,000 satoshis on 200 vbytes gives 10 sat/vB, while paying 2,000 on 400 vbytes gives 5 sat/vB. Comparing total fees alone can therefore be misleading.

Evidence: [Segregated Witness consensus layer](https://raw.githubusercontent.com/bitcoin/bips/927b6de9915c9262615a6399de51b200f81e5aa4/bip-0141.mediawiki); [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/)

## Read field names and units carefully

The cited Bitcoin Core 29.0 RPC distinguishes fee_rate in sat/vB from feeRate in BTC/kvB. The units differ by a factor of 100,000. A software integration should convert explicitly and reject an ambiguous input.

A wallet’s final fee can also change when coin selection or change construction changes the virtual size. Inspect the funded result, not only the requested rate.

Evidence: [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/)

## A target is not a booking

Fee estimation responds to observed transaction conditions and a desired confirmation target. Future arrivals and miner choices remain uncertain. A higher rate improves one part of the incentive but does not create a reservation.

For an unconfirmed transaction, consider the wallet’s replacement or child-spend options rather than treating a previous fee estimate as a promise.

Evidence: [Bitcoin Developer Guide: Transactions](https://developer.bitcoin.org/devguide/transactions.html); [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/)

## Questions

### Is the fee a percentage of the bitcoin I send?

No. The transaction fee is primarily a size-and-rate calculation, although the selected inputs and outputs must contain enough value to fund it.

Evidence: [Bitcoin Developer Guide: Transactions](https://developer.bitcoin.org/devguide/transactions.html); [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/)

## Claims and scope

### bitcoin-fee-rate-quick-answer

A Bitcoin fee rate measures fee paid per unit of transaction size, commonly satoshis per virtual byte. The total fee is the difference between input and output values. An estimated fee rate can inform a target, but it does not guarantee inclusion within a particular number of blocks.

Scope: {"collection":"bitcoin","dataAsOf":"2026-10-02","blockHeight":null}

### bitcoin-fee-rate-fact-total-fee

Total fee: Total input value minus total output value.

Scope: {"collection":"bitcoin","dataAsOf":"2026-10-02","blockHeight":null}

### bitcoin-fee-rate-fact-rate

Rate: Total fee in satoshis divided by virtual size gives sat/vB.

Scope: {"collection":"bitcoin","dataAsOf":"2026-10-02","blockHeight":null}

### bitcoin-fee-rate-fact-units

Units: 1 BTC per 1,000 vbytes equals 100,000 sat/vB.

Scope: {"collection":"bitcoin","dataAsOf":"2026-10-02","blockHeight":null}

## Sources

- [walletcreatefundedpsbt RPC](https://bitcoincore.org/en/doc/29.0.0/rpc/wallet/walletcreatefundedpsbt/) — Bitcoin Core. Input selection, fee units, change output, selected inputs and transaction funding. Locator: Arguments and result fields. Retrieved: 2026-10-02T17:03:40.827Z.
- [Bitcoin Developer Guide: Transactions](https://developer.bitcoin.org/devguide/transactions.html) — Bitcoin developer documentation contributors. UTXO inputs, transaction outputs, change and the difference paid as a fee. Locator: P2PKH Script Validation; Transaction Fees And Change. Retrieved: 2026-10-02T17:03:41.190Z.
- [Segregated Witness consensus layer](https://raw.githubusercontent.com/bitcoin/bips/927b6de9915c9262615a6399de51b200f81e5aa4/bip-0141.mediawiki) — Bitcoin BIPs contributors. Transaction weight and virtual-size definitions in the SegWit specification. Locator: Block size; Transaction size. Retrieved: 2026-10-02T17:22:20.465Z.

## Revision history

- 2026-10-02: Initial Bitcoin encyclopedia entry at this permanent URL.
- 2026-10-02: Added reusable claims, explicit source locators, and matching Markdown and JSON. This publishing change does not itself establish factual verification.

## Cite this entry

Degrees of Satoshi editorial project. “Bitcoin fee rates: sat/vB versus the total fee.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/bitcoin-fee-rate/