BTC Weight Calculator
Use this BTC weight calculator to estimate Bitcoin transaction weight units, witness bytes, total bytes, and virtual size from common input and output mixes.
Example Usage
- Estimate weight for a simple 1-input 2-output P2WPKH transaction.
- Compare how P2TR and P2PKH inputs change vbytes and weight.
- Check witness-heavy transactions before fee planning.
BTC Weight Calculator Explained
A BTC weight calculator helps you estimate how large a Bitcoin transaction is under SegWit sizing rules. Instead of only showing raw bytes, it separates base bytes, witness bytes, total weight units, and virtual bytes. That matters because Bitcoin fee rates are usually priced in satoshis per virtual byte, while witness data is discounted in the weight formula. This tool is useful for wallet flows, fee planning, transaction simulation, and comparing script types like P2WPKH, P2TR, and older legacy inputs. It is an estimator based on common template sizes, but for most front-end planning work that is exactly what you need.
FAQ
What is Bitcoin transaction weight?
Weight is the SegWit sizing metric that combines base bytes and witness bytes into a single fee-related value.
Why are vbytes different from raw bytes?
Because witness bytes are discounted under Bitcoin weight rules, so the billed virtual size can be smaller than total raw bytes.
Is this exact for every script path?
No. It uses common input and output templates, so unusual scripts may differ slightly.
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