How This Ethereum Gas Estimate Works
An Ethereum execution fee is Gas Used multiplied by the effective price paid for each unit of Gas. Under EIP-1559, the effective Gas Price is the estimated next-block Base Fee plus the effective priority fee, capped by Max Fee Per Gas. The calculator keeps the estimated actual fee separate from the maximum fee cap so the upper budget is not mistaken for the amount expected to be spent.
Every Gwei input is converted to whole Wei before multiplication. Gas fees are denominated in ETH; Gwei is the common display unit for price per Gas. The optional USD line is a secondary market conversion and does not alter the Wei, Gwei or ETH result. Use the ETH, Gwei and Wei Converter when the task is denomination conversion rather than transaction cost.
- Choose a safe Gas usage input
- Estimate the next-block Base Fee or enter it manually
- Apply the selected priority and Max Fee
- Resolve the effective Gas Price in whole Wei
- Calculate actual fee and maximum cap separately
Why Live Mode Estimates the Next-Block Base Fee
The Base Fee stored in the latest block is the parent value for the next block calculation. EIP-1559 adjusts the following block up when the parent used more than its Gas target and down when it used less. Live mode therefore reads the latest block Base Fee, Gas Used and Gas Limit, then applies the EIP-1559 integer formula to estimate the next-block Base Fee.
Low, Standard and High priority profiles come from the median 10th, 50th and 90th percentile rewards in recent eth_feeHistory data. They help compare fee inputs under the same Gas Used, but they do not guarantee confirmation time. The Show Calculation panel identifies the parent Base Fee, projected block number, provider time, fetch time and cache state.
When a Plain ETH Transfer Uses 21,000 Gas
The 21,000 Gas choice is limited to a plain ETH value transfer with no transaction data when the destination has no executable code. EIP-7702 allows an externally owned account to carry a delegation indicator that points to code. Sending to such an account can execute delegated code, so the fact that an address began as an EOA no longer proves that 21,000 Gas is enough.
Token transfers, approvals and dApp actions execute contract-specific paths. Their Gas depends on bytecode, call data, storage state and the path taken at execution time. This page intentionally does not publish universal fixed presets for those tasks. Enter the estimate from a wallet, application simulation or eth_estimateGas response instead.
Gas Used, Gas Limit and the EIP-7825 Cap
Gas Used estimates execution actually consumed. Gas Limit is the maximum execution budget made available to the transaction. Unused Gas is not charged as though it had been consumed, while an out-of-Gas failure can still consume the Gas spent before execution stops.
Ethereum Mainnet enforces a protocol-level per-transaction Gas Limit cap of 16,777,216 Gas, or 2^24, under EIP-7825. This is a transaction cap, not the block Gas Limit. The calculator rejects Gas Used or Gas Limit values above that boundary in HTML, JavaScript, server rendering and the REST endpoint.
| Result | Formula | Meaning |
|---|---|---|
| Estimated actual fee | Gas Used x effective Gas Price | Estimated ETH spent for execution |
| Maximum fee cap | Gas Limit x Max Fee Per Gas | Upper fee budget represented by the transaction fields |
| Effective priority fee | min(Max Priority, Max Fee - Base Fee) | Tip actually available under the fee cap |
Worked Ethereum Gas Fee Examples
For 21,000 Gas Used and a 21,000 Gas Limit with a 10 Gwei Base Fee, 2 Gwei Max Priority Fee and 22 Gwei Max Fee, the effective Gas Price is 12 Gwei. The estimated actual fee is 252,000,000,000,000 Wei, or 0.000252 ETH. The maximum cap is 462,000,000,000,000 Wei, or 0.000462 ETH.
If Max Priority is 5 Gwei but Max Fee is 12 Gwei while Base Fee is 10 Gwei, only 2 Gwei remains for effective priority. The effective Gas Price is therefore 12 Gwei, not 15 Gwei. For a user-supplied contract estimate of 150,000 Gas at 12 Gwei, the estimated execution fee is 0.0018 ETH; that example is arithmetic, not a universal contract preset.
What This Ethereum Gas Estimate Does Not Include
This page covers Ethereum Mainnet execution Gas. It does not calculate EIP-4844 blob Gas, rollup L1 data fees, bridge fees, sponsored transactions, ERC-4337 UserOperations, exchange withdrawals, MEV, refund behavior for a specific call or a wallet-specific simulation. It does not inspect destination code or EIP-7702 delegation state.
The optional USD value reuses the existing reviewed Ethereum market snapshot and is omitted when unavailable. Exact Wei, Gwei and ETH results remain independent of market price. A wallet can simulate the exact call closer to signing, so its current Gas estimate and transaction preview should take priority. For cross-network stablecoin costs, use the Stablecoin Transfer Fee Calculator.
Ethereum Gas Calculator FAQ
How do I calculate an Ethereum Gas fee?
Multiply Gas Used by the effective Gas Price. For EIP-1559, the effective price is Base Fee plus the effective priority fee, capped by Max Fee Per Gas.
What is the difference between Max Fee and Priority Fee?
Max Fee Per Gas caps the total price per Gas. Max Priority Fee Per Gas caps the validator tip, which can be reduced when Max Fee leaves less room after Base Fee.
When does an ETH transfer use 21,000 Gas?
Use 21,000 Gas only for a plain ETH transfer with no transaction data when the destination has no code or EIP-7702 delegation. A delegated account can execute code and require more Gas.
What is the Ethereum per-transaction Gas cap?
EIP-7825 caps one Ethereum Mainnet transaction at 16,777,216 Gas, or 2^24. This is separate from the block Gas Limit.
Why does live Base Fee differ from the latest block?
The latest block provides the parent Base Fee, Gas Used and Gas Limit. Live mode applies the EIP-1559 integer adjustment to estimate the Base Fee for the next block.
Are Low, Standard and High confirmation guarantees?
No. They summarize recent reward percentiles from Ethereum block data. Network demand and transaction selection can change after the estimate.
Can I calculate a legacy Gas Price transaction?
Yes. Manual legacy mode multiplies the entered Gas Price by Gas Used and uses Gas Limit for the maximum budget.
Why can my wallet show a different fee?
A wallet can inspect destination code, EIP-7702 delegation, call data and current state, then refresh network conditions closer to signing. This calculator does not perform that simulation or include Layer 2 fee components.
Methodology and Sources
The same server-side integer-Wei engine powers the initial page, REST recalculation, priority comparison, copied estimate and deterministic tests.
- Gwei inputs are converted to whole Wei before multiplication; browser floating-point arithmetic never owns the fee formula.
- EIP-1559 effective priority equals min(Max Priority Fee, Max Fee minus Base Fee).
- Actual fee uses Gas Used; maximum cap uses Gas Limit.
- Live mode derives the next-block Base Fee from the latest parent block Base Fee, Gas Used and Gas Limit with the EIP-1559 integer formula.
- Priority profiles use recent eth_feeHistory reward percentiles and are not confirmation guarantees.
- Gas Used and Gas Limit are rejected above the EIP-7825 cap of 16,777,216 Gas.
- The 21,000 Gas option is limited to a plain transfer with no data to an address without code or EIP-7702 delegation.
- Validated RPC results use short and last-known-good caches; missing live data remains unavailable while manual modes continue to work.
- ETH/USD is an optional secondary conversion from the existing Ethereum market cache.
Primary references
- Ethereum.org: Gas and Fees Gas, Base Fee, priority fee and practical fee formulas.
- EIP-1559 Type 2 fee fields, effective priority fee and fee-cap behavior.
- Ethereum.org: Transactions Transaction fields, Gas Limit and the 21,000 Gas ETH-transfer example.
- Ethereum JSON-RPC API Latest block and fee-history RPC method definitions.
- EIP-7702 Delegated-code behavior for externally owned accounts and the boundary of a plain transfer assumption.
- EIP-7825 Protocol-level 16,777,216 Gas cap for one transaction.
- Ethereum Foundation: Fusaka Mainnet Announcement Mainnet activation context for the EIP-7825 transaction Gas cap.
Reviewed by the BitcoinToolkit Editorial Team calculation logic last tested