Transaction Fee Estimator
Enter the fee rate your wallet or a block explorer is showing and this works out the cost in native units and, optionally, in dollars. It uses no market feed and no live network data — the arithmetic runs entirely on the numbers you type.
Bitcoin-style fee (sat/vB)
Enter a fee rate and a transaction size to see the total.
Formula: fee rate (sat/vB) × size (vB) = total satoshis; ÷ 100,000,000 = BTC.
Ethereum-style fee (gas)
Enter a gas limit and a base fee to see the total.
Formula: gas units × (base fee + priority fee) = gwei; ÷ 1,000,000,000 = ETH. A plain ETH transfer uses 21,000 gas units; token transfers and contract calls use more.
How to find the numbers to enter
- Fee rate: your wallet's send screen usually shows the rate it intends to use, and block explorers publish current rates.
- Transaction size: your wallet shows the estimated size once the recipient and amount are set. Transactions spending many small inputs are larger.
- Gas limit: wallets estimate this per transaction. The 21,000 figure applies only to a simple ETH transfer.
- Base fee: shown by wallets and explorers on Ethereum, and it changes block by block.
- Price: optional, and only used to convert the result. Nothing you type leaves your browser.
Frequently Asked Questions
Does this estimator use live network fees?
No. It takes the values you enter and does the arithmetic. Fee rates and prices change continuously, so read the current rate from your wallet or a block explorer and type it in.
What is a virtual byte (vB)?
Bitcoin fee rates are quoted per virtual byte, a measure of how much block space a transaction occupies. A simple single-input transfer is often in the low hundreds of vB; transactions with many inputs are larger and therefore cost more at the same rate.
Why is the Ethereum cost split into base fee and priority fee?
Ethereum charges a base fee per unit of gas that the protocol sets and burns, plus an optional priority fee paid to the block proposer. The total paid per unit of gas is the sum of the two, capped by the maximum fee you set.
Why did my actual fee differ from this estimate?
Fee rates move between the moment you read them and the moment your transaction is included, and the real size or gas used may differ from your assumption. Treat the output as arithmetic on your inputs, not a prediction.
Background reading: network fees explained, Ethereum gas explained and all calculators.