Ethereum Gas Fee Calculator

Estimate Ethereum gas fees from the gas price in Gwei and your gas limit — in ETH and USD. Presets or custom, computed in your browser with no RPC calls.

All calculations happen locally in your browser. Nothing leaves your device.

Fee (ETH)
0.00042 ETH
$1.26 at your entered ETH price

Gwei = 10⁻⁹ ETH (one-billionth of an ETH). Fee = gas limit × gas price × 10⁻⁹.

How It Works

Every Ethereum transaction pays a fee equal to the gas it consumes, priced in Gwei. This calculator does the multiplication for you: fee = gas limit × gas price × 10^-9 ETH.

What is Gwei?
Gwei is one-billionth of an ETH (10^-9). The network prices gas in Gwei per unit of gas, so a 20 Gwei price means each gas unit costs 0.000000020 ETH. Multiplying by 10^-9 converts the Gwei total into ETH.
What is the gas limit?
The gas limit is the maximum amount of gas your transaction is allowed to use — a budget cap, not a fixed cost. Plain transfers always consume exactly 21,000 gas; ERC-20 transfers and contract calls use more (50,000–150,000+). Only gas actually used is charged, so the real fee can come in below the limit.
The formula
Fee (ETH) = gas limit × gas price (Gwei) × 10^-9. Example: 21,000 × 20 × 10^-9 = 0.00042 ETH, which is $1.26 at an ETH price of $3,000. The USD figure is optional — it only appears when you enter an ETH price.

Frequently Asked Questions

What is Gwei?

Gwei is one-billionth of an ETH (10^-9). The Ethereum network prices gas in Gwei, so a 20 Gwei gas price means each unit of gas costs 0.000000020 ETH. To get the fee in ETH you multiply the gas limit by the gas price and divide by 1,000,000,000.

Why is 21,000 the default gas limit?

A plain ETH transfer always consumes exactly 21,000 gas — one base unit per byte of the standard transfer — so 21,000 is the natural default for this calculator. Contract interactions cost more (50,000–150,000+), and you can pick common presets or enter a custom limit.

Does the tool fetch real-time gas prices?

No. It never calls an RPC node or any external API — you type in the gas price you want to use (for example, one read from Etherscan or your wallet), and the calculator multiplies it by your gas limit. That keeps the tool fast, offline-friendly and completely private.

What does the USD value show?

It is an optional conversion. Enter an ETH price in USD (3,000 by default) and the tool multiplies your fee in ETH by that price to show what the transaction costs in dollars. Leave the field empty and only the ETH amount is shown. The price is never fetched from the web.

Is my data sent anywhere?

No. All calculations run locally in your browser with zero uploads and zero tracking. The gas price, gas limit and ETH price live only in this page and disappear when you close it.