Tool · Transactions
Fee calculator
What a transaction costs, from its size and a fee rate
What it does
Pick a fee rate and a transaction size and get the fee in grains and PRL. The size chips are real mainnet transactions; hover one to see what it actually paid.
How to read it
- Fee = fee rate × vsize. The rate is in grains per virtual byte; the result is rounded up to a whole grain.
- vsize is the transaction’s size with witness bytes counted at a quarter: base bytes + ⌈witness ÷ 4⌉. A simple payment (one input, two outputs) is about 154 vbytes.
- Miners fill blocks with the best-paying transactions per vbyte, so the rate, not the total, decides how soon a transaction is picked up.
Pearl specifics
- The relay minimum is 1 grain per vbyte. Below it, nodes won’t pass the transaction on.
- The dust limit is 333 grains: nodes won’t relay a Taproot or P2MR output worth less. OP_RETURN outputs are exempt.
- Pearl measures blocks in vbytes, up to 1,000,000 per block, and nodes don’t relay a single transaction over 100,000 vbytes. There are no “weight units”.
- In October 2026, wallets paid about 50 grains per vbyte; the example payment paid 7,915 grains for 154 vbytes (51.4 grains/vB). Some paid far less: the P2MR spend paid 4.3.
Under the hood
Runs entirely in your browser. The sizes and fees of the examples are real (Pearl Blockbook), and the vsize rule
is the one in src/lib/tx.ts, whose unit tests match every example’s size and vsize to the explorer’s.