Bitcoin Transaction Size Reference (vBytes by Input & Output Type)
How big is your Bitcoin transaction, and what will it cost? A reference for the virtual-byte (vByte) size of every transaction component — overhead, inputs and outputs by address type — so you can estimate the fee. Free CSV/JSON + REST under CC BY 4.0.
Quick answer
Bitcoin fees are paid per virtual byte (vByte), not per dollar — so a transaction's SIZE sets its fee, and size depends on how many inputs and outputs it has and which address types they use. A quick estimate: about 10.5 vB of fixed overhead, plus each input (148 vB for a legacy input down to ~57.5 vB for a Taproot input) and each output (31-43 vB). This is why newer address types are cheaper to spend — a native-SegWit input (68 vB) is roughly half a legacy one (148 vB), and Taproot is smaller still. This reference lists the typical vByte size of each of the 10 transaction components so you can size a transaction before you send it.
Estimate a fee like this: size (vB) = 10.5 + (sum of input sizes) + (sum of output sizes), then fee = size x your sat/vByte rate. Spending native-SegWit or Taproot inputs instead of legacy roughly halves the per-input cost — consolidate UTXOs during low-fee windows and prefer modern address types.
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| Component | Type | Size (vB) | Notes |
|---|---|---|---|
| Overhead | Fixed (per transaction) | 10.5 | Version, locktime and the input/output counts (plus the SegWit marker/flag on SegWit transactions). Counted once per transaction. |
| Input | P2PKH (Legacy '1') | 148 | A legacy input — by far the largest, which is why spending old '1' coins costs the most. |
| Input | P2SH-P2WPKH (Nested SegWit '3') | 91 | Native SegWit wrapped in P2SH; smaller than legacy, larger than native. |
| Input | P2WPKH (Native SegWit 'bc1q') | 68 | Native SegWit input — roughly half the size of a legacy input. |
| Input | P2TR (Taproot 'bc1p', key-path) | 57.5 | A Taproot key-path input — the smallest standard input, cheapest to spend. |
| Output | P2PKH (Legacy '1') | 34 | A legacy output. |
| Output | P2SH ('3') | 32 | A P2SH output (multisig or wrapped SegWit). |
| Output | P2WPKH (Native SegWit 'bc1q') | 31 | The smallest common output. |
| Output | P2WSH (Native SegWit script) | 43 | A native-SegWit script output (e.g. multisig). |
| Output | P2TR (Taproot 'bc1p') | 43 | A Taproot output. |
Pairs with D-Central’s Bitcoin address types reference and the live network vitals (current mempool fee tiers). Glossary: vByte, weight unit, sats per vByte. Typical single-sig sizes; multisig and unusual scripts differ.
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Last reviewed June 20, 2026.