Gas Fee Estimator – Live ETH, BNB & Base Gas Fees in Dollars
Gas is the toll every on-chain action pays — and on Ethereum it changes by the minute. This estimator reads the live gas price for Ethereum, BNB Chain and Base and turns it into the dollar cost of the things you actually do: a transfer, an approval, a swap, a mint.
Every blockchain transaction pays gas = gas used × gas price. A plain transfer always uses 21,000 gas; approvals, swaps and mints use more because the contracts do more work. The estimator asks the chain itself for the current gas price (the eth_gasPrice call to a public RPC endpoint) and prices the coin through CoinGecko's free API, then multiplies out four typical actions using standard gas amounts — 21,000 for a transfer, 46,000 for a token approval, 150,000 for a typical DEX swap and 145,000 for a typical NFT mint. If a live read ever fails, you get a clearly-labelled typical estimate instead of a blank page, with the source and fetch time shown either way.
How to use it
Pick the chain — Ethereum, BNB Chain or Base.
Read the live gas price — shown in Gwei, next to the coin's dollar price.
Find your action — the table prices a transfer, approval, swap and mint in the coin and in dollars.
Refresh before you transact — gas moves fast on Ethereum; Base and BNB Chain stay cheap and steadier.
What you get
Truly live — gas read from the chain's own RPC at the moment you open or refresh the tool.
Three chains — Ethereum, BNB Chain and Base side by side, one tap apart.
Dollar costs — every action priced in USD as well as in ETH or BNB.
Honest fallback — if a live read fails, a labelled typical estimate is shown, never passed off as live.
Frequently asked questions
How is a gas fee calculated?
Fee = gas used × gas price. Gas used depends on the action (a transfer is 21,000; a swap is roughly 150,000). Gas price is quoted in Gwei — one Gwei is 0.000000001 of the chain's coin — and it rises when the network is busy.
Why is Ethereum gas so much higher than Base or BNB Chain?
Ethereum mainnet has the most demand for limited block space. Base (an Ethereum layer-2) and BNB Chain process transactions more cheaply, so the same swap that costs dollars on mainnet usually costs cents there.
What is Gwei?
A small denomination of ETH: 1 ETH = 1,000,000,000 Gwei. Gas prices are quoted in Gwei because the raw ETH numbers would be long decimals.
Where does the data come from?
Gas price comes from the chain's public RPC (eth_gasPrice) and the coin price from CoinGecko's free API. The tool shows when the figures were fetched; press Refresh for a new read.