Step-by-step
- Note the unit on the screenshot. Explorers often show gwei for gas price and ETH for total fee. Wallet Review shows a fee in the native symbol.
- Convert on this page. Edit any one field. Arithmetic only. 21000 gas × 15 gwei is a simple-transfer sketch, not a swap.
- Compare with Send’s fee tier. Open Send in /app. If amount + fee exceeds balance you will see Insufficient funds including the network fee.
Gas units are not gwei
Gas is a count of work (21000 for a simple ETH transfer, far more for ERC-20 and swaps). Gwei is a price per gas. Total wei ≈ gasUsed × (baseFee + priority) in EIP-1559. Bridges can need a destination-side fee too — see gas fees when swapping and bridging.
| Unit | Wei | Where you see it |
|---|---|---|
| 1 wei | 1 | Raw tx value |
| 1 gwei | 1,000,000,000 | Gas price UI |
| 1 ether | 10^18 | Balances, Send amount |
L2s still denominate gas in ETH (or the L2’s native). Base fees can be tiny in USD and still block a send if your ETH on that L2 is zero.
What this converter cannot do
It cannot price BTC sat/vB, TRON energy, or Solana lamports. It cannot tell you if a swap quote expired. It will not sign anything.
fee_eth ≈ gas * gwei / 1e9
1e9 gwei = 1 ETH
GaurdWallet Send tiers = live estimate, not this sketchAnyone asking you to convert wei and then “approve unlimited” in a dApp is running a drain. Exchange uses exact-amount approvals.
FAQ
Is gwei the same on BNB Chain? BNB Chain uses the same 18-decimal native unit. People still say gwei for the gas price field. The native coin is BNB, not ETH.
Why does 15 gwei times 21000 not match Send? Swaps use more gas, EIP-1559 has two fee fields, and L2s differ. The Review row is authoritative.
Can I enter wei with decimals? Wei are integers. The widget will still do IEEE math — treat fractional wei as a sketch, not a tx field.