Encyclopedia How the network works · Entry 82
Bitcoin dust: a relay-policy threshold, not a smallest coin
In this article
At a glance
Key facts
| Fact | Detail | Source |
|---|---|---|
| Unit | An amount can be denominated in whole satoshis and still count as dust under relay policy. | [1] |
| Script | Different output types have different estimated spending costs. | [1] |
| Policy | Relay acceptance and consensus validity answer different questions. | [1][2] |
Why one fixed number is misleading
Bitcoin Core v29.0 calculates a dust threshold using the output’s serialized size, an estimate of the input needed to spend it and a dust relay fee. Its treatment distinguishes witness and non-witness spending costs.
Quoting a single dust threshold without identifying the script and policy setting omits part of the rule. Some provably unspendable outputs are treated differently because they are not expected to require a later spend.
A small output can become costly to use
For illustration, if adding an input costs about 70 virtual bytes and the chosen fee rate is 20 sat/vB, that input contributes about 1,400 satoshis to the fee estimate. A 500-satoshi receipt would add less value than that illustrative marginal fee. Actual sizes depend on the script and signature.
This economic comparison is separate from a node’s configured dust policy. Fee conditions can change, and a wallet may have other reasons for spending or excluding an output.
Unexpected small receipts do not authorize spending
Receiving a tiny output does not reveal a private key or require you to spend it. Combining that receipt with other coins can create additional public relationships, so a wallet’s coin-control tools may be relevant.
Avoid treating every tiny receipt as either harmless income or proof of a successful attack. Inspect its provenance and how your wallet would select it.
Direct answers
Questions people ask
Is one satoshi always a relayable output?
No. One satoshi is an amount unit. A node can reject an otherwise valid transaction from its mempool under dust or other relay policy.
Inspect the evidence
The answer and key facts have stable claim links. These records retain the scope and qualification when reused.
In Bitcoin Core relay policy, dust is an output whose value is small relative to its estimated spending cost at the configured dust relay fee. It is not a universal minimum amount enforced by Bitcoin consensus, and the threshold depends on the output’s script type and node policy.
Scope: Bitcoin · data through 2026-10-02. Verification: verified · 2026-10-02T18:15:23.891Z.
Link to this claimUnit: An amount can be denominated in whole satoshis and still count as dust under relay policy.
Scope: Bitcoin · data through 2026-10-02. Verification: verified · 2026-10-02T18:15:23.891Z.
Link to this claimScript: Different output types have different estimated spending costs.
Scope: Bitcoin · data through 2026-10-02. Verification: verified · 2026-10-02T18:15:23.891Z.
Link to this claimPolicy: Relay acceptance and consensus validity answer different questions.
Scope: Bitcoin · data through 2026-10-02. Verification: verified · 2026-10-02T18:15:23.891Z.
Link to this claimRevision history
- — Initial Bitcoin encyclopedia entry at this permanent URL.
- — Added reusable claims, explicit source locators, and matching Markdown and JSON. This publishing change does not itself establish factual verification.
Source register
Sources and references
Retrieval dates and locators are recorded individually.- Bitcoin Core relay-policy implementationBitcoin Core
Dust depends on script spend cost and relay-fee policy, not a consensus minimum.
Locator: GetDustThreshold; IsDust · Version / scope: Bitcoin Core v29.0 · Retrieved: 2026-10-02T17:03:40.248ZOpen source - Bitcoin Developer Guide: TransactionsBitcoin developer documentation contributors
UTXO inputs, transaction outputs, change and the difference paid as a fee.
Locator: P2PKH Script Validation; Transaction Fees And Change · Retrieved: 2026-10-02T17:03:41.190ZOpen source - Segregated Witness consensus layerBitcoin BIPs contributors
Transaction weight and virtual-size definitions in the SegWit specification.
Locator: Block size; Transaction size · Version / scope: BIP-141; immutable revision pinned in source URL · Retrieved: 2026-10-02T17:22:20.465ZOpen source - walletcreatefundedpsbt RPCBitcoin Core
Input selection, fee units, change output, selected inputs and transaction funding.
Locator: Arguments and result fields · Version / scope: Bitcoin Core 29.0.0 RPC · Retrieved: 2026-10-02T17:03:40.827ZOpen source - Bitcoin Developer Guide: WalletsBitcoin developer documentation contributors
Spending keys, address derivation, backups and privacy trade-offs.
Locator: Wallet Programs; Public Key Distribution-Only Wallets; Hierarchical Deterministic Key Creation · Retrieved: 2026-10-02T17:03:41.163ZOpen source - lockunspent RPCBitcoin Core
Preventing specified wallet outputs from automatic coin selection.
Locator: Arguments and result fields · Version / scope: Bitcoin Core 29.0.0 RPC · Retrieved: 2026-10-02T17:03:41.086ZOpen source - Bitcoin: A Peer-to-Peer Electronic Cash SystemSatoshi Nakamoto
Most-work chain selection, Merkle inclusion, SPV limits and transaction change.
Locator: Sections 4–5 and 7–11 · Version / scope: 2008 paper · Retrieved: 2026-10-02T17:03:41.335ZOpen source
Research and drafting use AI assistance. A separate automated review checks claims against primary sources; no external expert or named human review is implied. Publication, substantive editing, source retrieval and verification are recorded separately. This version was independently checked by an automated reviewer on 2 October 2026.
Editorial method and correctionsDegrees of Satoshi editorial project. “Bitcoin dust: a relay-policy threshold, not a smallest coin.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/bitcoin-dust/