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Gwei Calculator
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Use this simple gwei calculator to get your fee estimates for Ethereum.
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Skip the napkin math. Estimate fees across chains, compare costs, and ship fee UX with Tatum's Fee Estimation.
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What is Wei?
In Ethereum, wei is the base unit of ether — 1 ETH = 10¹⁸ wei. The name honors Wei Dai, a cypherpunk who conceptualized b-money. Ether powers computation on the network ("gas"); transaction fees are gas used × gas price, paid for the compute resources consumed.
How is Wei calculated?
Multiply ether by 10¹⁸ to get wei; divide wei by 10¹⁸ to get ether. That precision avoids floating-point issues when specifying tiny amounts. Cheat sheet:
| Unit | Wei | Gwei | Ether |
|---|---|---|---|
| Wei | 1 | 10⁻⁹ | 10⁻¹⁸ |
| Kwei | 10³ | 10⁻⁶ | 10⁻¹⁵ |
| Mwei | 10⁶ | 10⁻³ | 10⁻¹² |
| Gwei | 10⁹ | 1 | 10⁻⁹ |
| Microether | 10¹² | 10³ | 10⁻⁶ |
| Milliether | 10¹⁵ | 10⁶ | 10⁻³ |
| Ether | 10¹⁸ | 10⁹ | 1 |
FAQ
- What is Wei?
- Wei is the smallest denomination of ether: 1 ETH = 10¹⁸ wei. Gas prices and many low-level Ethereum APIs work in wei or gwei.
- How is Gwei related to Ether?
- 1 Gwei = 10⁹ wei = 10⁻⁹ ETH. Wallet fee UIs often show gas price in Gwei while settlement still happens in wei.
- How is transaction fee calculated?
- Fee (ETH) ≈ gas price (Gwei) × gas used ÷ 10⁹. Multiply by the ETH/USD rate for a dollar estimate. Real fees also depend on base fee and priority tip at inclusion time.