Estimate input weight, witness size, control-block size, fee contribution and the Merkle path revealed by a Taproot script-path spend.
How it works
The calculator applies the documented Bitcoin or BIP rule to the values you enter and returns a mathematical or serialization estimate. Protocol implementation details and real wallet behavior remain authoritative.
The formula
Tapscript size (bytes) • Merkle path depth • Schnorr signature count • Signature size • Additional witness items • Bytes per additional item • Fee rate (sat/vB)
Worked example
34-byte Tapscript, Merkle depth 2 and one 64-byte signature → 97-byte control block and 90.75 vB input contribution.
For educational and technical analysis only. Not financial advice, security auditing, wallet software or a guarantee of fund safety. Verify current BIPs and your wallet implementation before using real funds. Never enter a seed phrase or private key into a website.
Frequently asked questions
What does this calculator estimate?
Estimate input weight, witness size, control-block size, fee contribution and the Merkle path revealed by a Taproot script-path spend.
Should I enter a seed phrase or private key?
No. Never enter a recovery phrase, seed phrase or private key into this or any web calculator. These tools are designed to work without secret key material.
Is the result a security or financial guarantee?
No. It is an educational technical estimate based on the selected assumptions and cited specifications. Real software, wallet policy, network rules and correlated failures can change outcomes.