Bitcoin Transaction Fee Calculator
Estimate a Bitcoin fee
Current Bitcoin fee rates
Manual mode makes no network requests. Choosing live mode sends a read-only request to mempool.space; no transaction or wallet data is sent.
Manual mode is active. Enter any custom rate below, or load current recommendations.
Custom fee estimate
0.00001410 BTC for 141 vB at 10 sat/vB| Priority | Rate | Target estimate | Fee (sats) | Fee (BTC) | Fiat (USD) | % of amount |
|---|
Load live rates to compare speed and cost. The custom estimate remains available in manual mode.
Virtual size = ceil(562 weight units ÷ 4) = 141 vB
Total fee = ceil(141 vB × 10 sat/vB) = 1,410 sats
BTC fee = 1,410 ÷ 100,000,000 = 0.00001410 BTC
Fiat fee = BTC fee × BTC price (when provided)
Worked example: 141 vB × 10 sat/vB = 1,410 sats = 0.00001410 BTC. A fractional product is rounded up because a transaction cannot pay part of a satoshi.
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How to estimate inputs and outputs
An input is a previously received UTXO your wallet spends. An output is a destination: usually one payment plus one change output. Your wallet may choose several inputs to cover the payment.
Use its preview if available. Otherwise, start with Simple payment, choose the address types you are spending from and sending to, and include change. The payment amount does not change transaction weight.
Address-type size reference
| Type | Input assumption | Output size |
|---|---|---|
| Legacy P2PKH | 148 vB | 34 bytes |
| Nested P2WPKH | 91 vB | 32 bytes (P2SH) |
| Native P2WPKH | 68 vB | 31 bytes |
| Taproot key path | 57.5 vB | 43 bytes |
Choosing a confirmation target
Priority aims for the next block, Standard for roughly three blocks, and Economy for roughly six. At Bitcoin's average ten-minute block interval, those are approximately 10, 30, and 60 minutes—but blocks and demand are unpredictable.
Live recommendations summarize the public mempool seen by the provider. They are estimates, not guarantees; wallet estimates can differ because nodes see different transactions and use different algorithms.
Reduce fees and handle a stuck transaction
Wait for quieter demand, use SegWit addresses, batch payments, and consolidate small UTXOs when rates are low. Avoid unnecessary inputs, but do not sacrifice wallet privacy merely to save a small fee.
If a payment is stuck, use RBF when the wallet supports replacement, or CPFP to spend an output with a fee high enough for the combined package. Do not rebroadcast conflicting transactions without understanding wallet behavior.
Methodology and limitations
The estimator uses typical single-signature sizes: 592 WU per legacy P2PKH input, 364 WU per nested P2WPKH input, 272 WU per native P2WPKH input, and 230 WU per Taproot key-path input. Outputs use 136, 128, 124, and 172 WU respectively. Overhead includes version, locktime, input/output count varints, and the 2-WU SegWit marker and flag when needed; a legacy input in a mixed SegWit transaction also needs a 1-WU empty witness field.
Virtual size follows BIP 141: weight divided by four and rounded up. Transaction structure is described in the Bitcoin developer guide. Optional live fee recommendations and fiat prices come from mempool.space's public API.
Signatures, scripts, multisig policies, varint boundaries, wallet coin selection, change, and unusual data can change the final size. This is an estimate; the wallet's final signed transaction is authoritative. Live data is a snapshot from one provider and confirmation times are never guaranteed.
Prepared by Starlight Tools. Methodology updated 15 July 2026. No independent technical reviewer is claimed.
Bitcoin fee calculator FAQs
How are Bitcoin transaction fees calculated?
Multiply the signed transaction's virtual size in vbytes by its fee rate in satoshis per vbyte, then round the total up to a whole satoshi.
Does the amount of Bitcoin sent change the network fee?
No. Bitcoin network fees depend mainly on transaction data weight—especially the number and types of inputs and outputs—not the BTC value sent.
What do sat/vB and vbytes mean?
sat/vB means satoshis paid per virtual byte. A vbyte is one quarter of four weight units, with the final transaction vsize rounded up.
How do I find a Bitcoin transaction's size?
Before sending, use the wallet's fee preview or estimate the inputs and outputs here. After signing or broadcasting, use the wallet or a block explorer's vsize field.
Why do inputs increase the fee so much?
Each input includes a reference and unlocking data such as a signature. Spending many small UTXOs therefore consumes more block space than spending one larger UTXO.
Which Bitcoin fee rate should I choose?
Choose Priority for urgency, Standard for a balance of time and cost, or Economy when you can wait. All targets shown here are estimates, not guarantees.
Why does my wallet estimate differ?
Wallets may select different UTXOs, add a change output, use different signature sizes, or consult a different node and fee-estimation algorithm. Trust the final signed transaction size.
Will 1 sat/vB confirm?
It may confirm during quiet periods, but it can wait indefinitely or fall below a node's current mempool minimum during congestion. Check current conditions before broadcasting.
How do RBF and CPFP work?
Replace-by-Fee replaces an eligible unconfirmed transaction with a higher-fee version. Child-Pays-for-Parent spends one of its outputs with enough fee for miners to select the package.
Is a network fee the same as an exchange withdrawal fee?
No. A Bitcoin network fee pays miners for block space. An exchange may charge its own withdrawal fee, which can include service costs and need not equal the network fee.
Can I use this calculator for Ethereum gas?
No. Ethereum uses gas units, base fees, and priority fees rather than Bitcoin transaction weight and sat/vB. Use an Ethereum-specific gas calculator.