Smart contracts use Wei (smallest unit), wallets show ETH, and gas prices are in Gwei. The Wei ↔ Gwei ↔ ETH converter converts between these units with BigInt precision so you can read contract values, set gas price, or convert user-facing ETH amounts for contract calls—all in the browser with no data sent to any server.
Why convert between Wei, Gwei, and ETH?
Smart contracts use Wei (the smallest unit), wallets display ETH, and gas prices are quoted in Gwei. Accurate conversions are essential for development and debugging. The converter supports Wei, Gwei, and ETH with BigInt for full precision, matching smart contract math. All conversions are performed locally in your browser. Use it when reading contract values in Wei, setting gas price in Gwei, or converting user-facing ETH amounts for contract calls.
Key Features
- Why convert — Contracts use Wei, wallets use ETH, gas uses Gwei. Conversions are essential for dev and debugging.
- Wei — Smallest denomination of Ether. 1 ETH = 10¹⁸ Wei.
- Gwei — Commonly used for gas prices. 1 ETH = 10⁹ Gwei.
- Precision — All calculations use BigInt. No precision loss; matches smart contract math.
- Privacy — All conversions are performed locally in your browser.
- When to use — Reading contract values in Wei, setting gas in Gwei, converting ETH for contract calls.
How to Use the Wei ↔ Gwei ↔ ETH Converter
- Open the Wei ↔ Gwei ↔ ETH tool.
- Enter value in Wei, Gwei, or ETH. View equivalent in other units. Copy as needed.
- Use the "Use tool" button on the docs page if you are reading this from the documentation.
Real Use Cases
- Contract values — Read balance or amount in Wei from contract. Convert to ETH for display. Use with Hex-Decimal Converter when decoding hex uint256. Use with Checksum Address Generator and Keccak256 Hasher when working with addresses and hashes.
- Gas price — Set or interpret gas price in Gwei. Convert to Wei for transaction building. Use with Hex-Decimal Converter.
- User-facing amounts — User enters ETH; convert to Wei for contract call. Use with ABI Encoder & Decoder for calldata.
- Documentation — Show team unit relationships. Use output as reference.
- Support — Explain “why is my balance in Wei?” Convert to ETH for users. Use with Hex-Decimal Converter.
- Testing — Assert contract amounts in Wei; display in ETH in tests. One converter for all units.
Why Use the Wei/Gwei/ETH Converter Instead of Alternatives?
- vs. Hex-Decimal Converter — Hex-Decimal Converter converts hex to decimal numbers. This tool converts ETH units (Wei, Gwei, ETH). Use hex-decimal for raw uint256; use this for token units.
- vs. Checksum Address Generator — Checksum Address Generator handles addresses. This tool handles amounts. Use the right tool for the task.
- vs. Keccak256 Hasher — Keccak256 Hasher hashes data. This tool converts units. Use hasher for hashing; use this for amounts.
- vs. Manual math — No risk of precision loss. BigInt-based; matches contract behavior.
Benefits for Smart Contract Developers
- Developers — Convert between Wei, Gwei, and ETH with full precision. Read contract values and set gas.
Common Mistakes
- Precision loss — This tool uses BigInt; no loss. If you use floating-point elsewhere, match with this tool’s values.
- Wrong unit — Confirm whether value is Wei, Gwei, or ETH. 1 ETH = 10¹⁸ Wei = 10⁹ Gwei.
- Expecting hex — This tool does not output hex. For hex uint256 use Hex-Decimal Converter.
- Forgetting to copy — Copy the result before closing the tab.
Frequently Asked Questions
Why convert between Wei, Gwei, and ETH?
Smart contracts use Wei (the smallest unit), wallets display ETH, and gas prices are quoted in Gwei. Accurate conversions are essential for development and debugging.
What is Wei?
Wei is the smallest denomination of Ether. 1 ETH = 1,000,000,000,000,000,000 (10¹⁸) Wei.
What is Gwei?
Gwei is commonly used for gas prices. 1 ETH = 1,000,000,000 (10⁹) Gwei.
Does this converter lose precision?
No. All calculations use BigInt for full precision, matching smart contract math.
Is my conversion data private?
Yes. All conversions are performed locally in your browser.
When should I use the Wei/Gwei/ETH converter?
Use it when reading contract values in Wei, setting gas price in Gwei, or converting user-facing ETH amounts for contract calls.
Wei ↔ Gwei ↔ ETH gives you unit conversion in one place: enter value in any unit, get equivalents with full precision. No server, no account. For hex numbers use Hex-Decimal Converter, for addresses use Checksum Address Generator, and for hashing use Keccak256 Hasher.
Use the Wei ↔ Gwei ↔ ETH tool to convert Ethereum units.