BTC Transaction Size Calculator
Use this BTC transaction size calculator to estimate transaction size from common input and output script types and compare vbytes with weight units.
Example Usage
- Estimate the size of a simple 1-input 2-output segwit transaction.
- Compare how different input types affect virtual size.
- Check rough vbytes before estimating a target fee rate.
BTC Transaction Size Calculator Explained
A BTC transaction size calculator gives you a quick estimate of how large a Bitcoin transaction is likely to be based on common input and output script types. This matters because Bitcoin fees are usually priced per virtual byte, so transaction size directly affects cost. By selecting script types such as P2PKH, P2WPKH, nested segwit, or taproot, and entering input and output counts, you can estimate bytes, vbytes, and weight units. This is useful for wallet UIs, fee planning, transaction previews, and rough cost comparisons before you build the final transaction.
FAQ
What is a virtual byte or vbyte?
A virtual byte is a size unit derived from transaction weight and commonly used for Bitcoin fee pricing.
Why do segwit transactions often have lower vbytes?
Because witness data is discounted in the Bitcoin weight formula, reducing effective fee size.
Is this an exact size calculator?
It is an estimate based on common script templates, which is useful for planning even if the final transaction differs slightly.
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