gas

Monad's gas pricing is EIP-1559 compatible but differs from Ethereum in critical ways. If you're building apps that submit transactions, estimate gas, or display gas costs, you need to understand these differences.

Key Difference: Monad Charges on Gas Limit, Not Gas Used

On Ethereum, users pay for the gas actually consumed by their transaction. On Monad, users pay based on the gas limit they set:

gas_paid = gas_limit * price_per_gas

This exists because Monad uses asynchronous execution — block leaders build blocks before executing them, so actual gas consumption isn't known at inclusion time. This prevents DOS attacks where transactions claim cheap gas but consume expensive computation.

What this means for developers:

• Setting an unnecessarily high gas limit directly costs users more MON.
• Always set tight, accurate gas limits especially for transactions with known fixed costs.
• For native MON transfers, the gas cost is always 21,000. Hardcode this instead of relying on eth_estimateGas.

EIP-1559 Transaction Pricing

Monad uses type 2 (EIP-1559) transactions:

price_per_gas = min(base_price_per_gas + priority_price_per_gas, max_price_per_gas)

Users specify two values when signing:

• priority_price_per_gas — tip for transaction prioritization within a block
• max_price_per_gas — safety cap on total gas price

The network controls base_price_per_gas, which is the same for all transactions in a block.

Block and Transaction Limits

These are significantly higher than Ethereum's 30M block gas limit, which means Monad blocks can fit more transactions.

Base Fee Controller

Monad's base fee controller is different from Ethereum's. It increases more slowly and decreases more quickly to prevent blockspace underutilization from overpricing.

Controller parameters:

• max_step_size = 1/28
• target = 160M gas (80% of block capacity)
• beta = 0.96
• epsilon = 160M

The base fee updates each block using an exponential adjustment based on how full the block was relative to the target. The formula uses exponential smoothing (beta = 0.96) to track historical variance in block fullness, producing smoother fee transitions than Ethereum's simpler mechanism.

In practice, this means gas prices on Monad are more stable and recover faster after spikes.

Transaction Ordering

The default Monad client orders transactions using a Priority Gas Auction, transactions are sorted by descending total gas price (base fee + priority fee).

Developer Guidelines

Always Set Explicit Gas Limits for Known Costs

For operations with fixed gas costs, set the gas limit explicitly before submitting to wallets:

// Good: explicit gas limit for a native transfer
const tx = {
  to: recipient,
  value: parseEther("1.0"),
  gasLimit: 21000n,
};

This is important because some wallets (like MetaMask) use eth_estimateGas to determine the gas limit. If that call reverts (e.g., the contract call would fail), the wallet may fall back to a very high gas limit. On Monad, the user would then pay for that entire inflated limit since gas is charged on the limit, not on actual usage.

Gas Estimation in Frontend Code

When using viem or wagmi to estimate gas, remember that the estimate is what users will actually pay not a lower bound. Add only a small buffer if needed:

// If you must estimate, keep the buffer small
const estimate = await publicClient.estimateGas({ ... });
const gasLimit = estimate + (estimate / 10n); // 10% buffer at most

Displaying Gas Costs to Users

When showing gas costs in your UI, calculate from the gas limit (not "gas used" from receipts on other chains):

const gasCost = gasLimit * gasPrice;

Smart Contract Considerations

• Monad's 30M transaction gas limit is the same as Ethereum's block gas limit, so individual transactions can be very large.
• Optimize your contracts to use less gas on Monad this directly saves users money since they pay for the limit, and tighter estimates mean tighter limits.
• If your contract has functions with predictable gas costs, document them so frontends can set explicit limits.

Opcode Pricing Differences

Monad adjusts a few opcode prices upward rather than discounting everything. This achieves the same relative effect with minimal disruption. The changes reflect different resource scarcity in Monad's high-performance architecture, particularly for disk-based state operations.

Cold State Access is Much More Expensive

Affected opcodes:

• Account access: BALANCE, EXTCODESIZE, EXTCODECOPY, EXTCODEHASH, CALL, CALLCODE, DELEGATECALL, STATICCALL, SELFDESTRUCT
• Storage access: SLOAD, SSTORE

What this means for developers:

• Contracts that touch many cold storage slots or call many external contracts will cost significantly more on Monad.
• Warm access is identical to Ethereum, so accessing the same slot/account repeatedly within a transaction has no extra cost.
• Batch operations that access a storage slot once (cold) and then reuse it (warm) are fine. But patterns that do single cold reads across many different slots will be more expensive.
• If your contract reads from many different storage slots in a single call, the gas estimate will be higher on Monad. Account for this when setting gas limits.

Precompile Repricing

Cryptographic precompiles cost 2-5x more on Monad:

What this means for developers:

• Contracts relying heavily on signature verification (ecRecover) will use 2x the gas for those operations.
• ZK-related operations (ecMul, ecPairing, point evaluation) are 4-5x more expensive. If your contract does on-chain ZK proof verification, gas estimates from Ethereum will be significantly off.
• Factor these higher precompile costs into gas limit calculations if your contract uses them.