Bitcoin UTXO Size Calculator
Calculate UTXO storage size and transaction fees for Bitcoin
Total Size
Estimated Fee
Efficiency Score
UTXO Set Value
Inputs Size
Outputs Size
Transaction Overhead
Total number of UTXOs you plan to spend in the transaction
Average amount in each UTXO (1 BTC = 100,000,000 sats)
Number of new UTXOs to create (usually 2: recipient + change)
Current market range: 5-150 sat/vB
For USD fee and UTXO value calculations
UTXO Optimization Tips
✅ Do:
- • Use SegWit (bc1) or Taproot addresses
- • Consolidate small UTXOs when fees are low
- • Batch transactions when possible
- • Keep UTXO count manageable (under 100)
❌ Avoid:
- • Creating many tiny UTXOs (<10k sats)
- • Using legacy P2PKH addresses (1...)
- • Spending during high fee periods unnecessarily
- • Creating UTXOs with odd amounts (dust)
Frequently Asked Questions
UTXO stands for Unspent Transaction Output. It's the fundamental unit of Bitcoin transactions. Each UTXO represents a specific amount of bitcoin that hasn't been spent yet and can be used as input in future transactions.
UTXO size refers to the data storage required for each UTXO in the Bitcoin blockchain. Larger UTXOs increase blockchain bloat, node storage requirements, and transaction fees. Efficient UTXO management helps keep the network healthy and fees low.
UTXO size depends on: 1) Number of inputs (previous UTXOs being spent), 2) Number of outputs (new UTXOs created), 3) Script type (P2PKH, P2SH, P2WPKH, etc.), 4) Transaction metadata like signatures and public keys.
P2PKH (Pay-to-Public-Key-Hash): Legacy addresses starting with '1', ~148 bytes per input. P2SH (Pay-to-Script-Hash): Multi-sig addresses starting with '3', ~91 bytes. SegWit (P2WPKH): Native SegWit starting with 'bc1', ~68 bytes (more efficient).
UTXO consolidation combines multiple small UTXOs into fewer larger ones. This reduces future transaction sizes and fees. Consolidate when you have many small UTXOs and fees are low, but be mindful of privacy implications.
Transaction fees are calculated based on transaction size in bytes (virtual bytes for SegWit). More UTXO inputs = larger transaction size = higher fees. Using SegWit addresses and consolidating UTXOs can significantly reduce fees.