What is Bitcoin Dust?
Bitcoin dust refers to tiny amounts of Bitcoin that are uneconomical to spend because the transaction fee required to move them exceeds their value. When you have a UTXO (Unspent Transaction Output) worth less than the cost to include it in a transaction, that UTXO is effectively unusable.
The dust threshold depends on two factors: the fee rate (sat/vB) you are willing to pay and the input size of your address type. Different Bitcoin address formats have different input sizes, meaning their dust thresholds vary significantly.
Why Dust Matters for Wallet Management
Dust UTXOs are problematic for several reasons:
- Unusable funds - You cannot spend them without losing money on fees
- Wallet bloat - They clutter your wallet with unspendable outputs
- Privacy concerns - Dust can be used in dust attacks to track wallet activity
- UTXO set growth - Dust contributes to the global UTXO set that all nodes must store
During high-fee periods, UTXOs that were previously spendable can become dust. Managing your UTXOs proactively helps avoid accumulating these unspendable fragments.
Address Type Comparison
The type of Bitcoin address you use significantly affects your dust threshold:
- Legacy (P2PKH) - 148 vBytes per input. The original address format starting with "1". Most expensive to spend.
- Nested SegWit (P2SH-P2WPKH) - 91 vBytes per input. Addresses starting with "3". Compatible with older software.
- Native SegWit (P2WPKH) - 68 vBytes per input. Addresses starting with "bc1q". The most common format today.
- Taproot (P2TR) - 57.5 vBytes per input. Addresses starting with "bc1p". The most efficient format, reducing dust threshold by 61% compared to legacy.
Dust Threshold = Input Size (vBytes) x Fee Rate (sat/vB)How to Avoid Creating Dust
Prevent dust accumulation with these strategies:
- Use modern address types - Taproot and Native SegWit have lower dust thresholds
- Consolidate during low fees - Combine small UTXOs when fees are cheap (under 5 sat/vB)
- Avoid small change outputs - Set minimum change thresholds in your wallet
- Use coin control - Manually select which UTXOs to spend to avoid creating tiny change
- Consider fee bumping costs - Leave enough for potential RBF fee increases
Frequently Asked Questions
What is the Bitcoin dust limit?
Bitcoin Core defines a dust limit as 3 times the minimum relay fee (typically 1 sat/vB) multiplied by the input size. For a P2WPKH output, this is about 294 sats at minimum fees. However, the practical dust threshold is higher - it is whatever amount costs more to spend than it is worth at your chosen fee rate.
Can I recover dust UTXOs?
Yes, during low-fee periods when fees drop to 1-5 sat/vB, previously uneconomical UTXOs may become spendable. Some wallets offer UTXO consolidation features that help you combine small amounts when fees are low.
What is a dust attack?
A dust attack involves sending tiny amounts of Bitcoin to many addresses to track when they are spent. When victims consolidate dust with their other UTXOs, attackers can link addresses together. Most wallets now flag suspicious small incoming amounts.
Why is Taproot more efficient than SegWit?
Taproot uses Schnorr signatures which are more compact than ECDSA signatures used in SegWit. A Taproot input is 57.5 vBytes compared to 68 vBytes for Native SegWit, a 15% reduction that lowers both transaction fees and dust thresholds.
Should I consolidate my UTXOs?
Consolidating during low-fee periods can reduce future transaction costs and prevent dust accumulation. However, it also merges your transaction history which has privacy implications. Consider your privacy needs alongside fee optimization.
Does Lightning Network have dust problems?
Lightning channels have a dust limit for HTLCs (usually 354 sats) but day-to-day Lightning payments do not create on-chain UTXOs. This is one reason Lightning is ideal for small payments - no dust accumulation.
How does fee rate affect dust threshold?
The relationship is linear - double the fee rate, double the dust threshold. At 10 sat/vB, Native SegWit dust is 680 sats. At 100 sat/vB, it jumps to 6,800 sats. During fee spikes, many UTXOs that were previously spendable become dust.
What happens to dust I cannot spend?
Dust UTXOs remain in your wallet indefinitely. They are not lost - just uneconomical to move. If fees drop significantly in the future, they may become spendable again. Some services offer dust sweeping, though fees often make this impractical.
Skip Dust Problems
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