calculateFeeForUserOperation

Calculates the total fee for a ZeroDev user operation given its gas limits and max fee per gas. Returns fee data in native units (wei), human-readable format (ETH), and optionally USD. Unlike estimateUserOperationGas, this function is synchronous and does not make any network calls — it computes the fee from gas values you already have (e.g., after calling estimateUserOperationGas or building a user operation manually).

Installation

npm install @dynamic-labs-sdk/zerodev

Usage

import { calculateFeeForUserOperation, estimateUserOperationGas } from '@dynamic-labs-sdk/zerodev';
import { getNetworksData } from '@dynamic-labs-sdk/client';
import { parseGwei } from 'viem';

const networks = getNetworksData();
const networkData = networks.find((n) => n.networkId === '1');

const feeData = calculateFeeForUserOperation({
  userOperationData: {
    callGasLimit: 100_000n,
    verificationGasLimit: 50_000n,
    preVerificationGas: 21_000n,
    maxFeePerGas: parseGwei('50'),
  },
  networkData,
});

console.log(`Estimated fee: ${feeData.humanReadableAmount} ETH`);

Parameters

Parameter	Type	Description
`userOperationData`	`object`	Gas values for the user operation
`userOperationData.callGasLimit`	`bigint`	Gas limit for the call phase
`userOperationData.verificationGasLimit`	`bigint`	Gas limit for the verification phase
`userOperationData.preVerificationGas`	`bigint`	Fixed pre-verification gas overhead
`userOperationData.maxFeePerGas`	`bigint`	Maximum fee per gas unit in wei
`networkData`	`NetworkData`	Network configuration. Get this from `getNetworksData()`
`nativeTokenPriceUsd`	`number` (optional)	USD price of the native token, used to calculate `usdAmount`

Returns

EvmTransactionFeeData (synchronous — not a Promise):

Field	Type	Description
`nativeAmount`	`bigint`	Total fee in wei: `(callGasLimit + verificationGasLimit + preVerificationGas) × maxFeePerGas`
`humanReadableAmount`	`string`	Fee in ETH, formatted for display
`usdAmount`	`string` (optional)	Fee in USD. Present only when `nativeTokenPriceUsd` is provided
`gasEstimate`	`bigint`	Total gas units: `callGasLimit + verificationGasLimit + preVerificationGas`
`maxFeePerGas`	`bigint`	The `maxFeePerGas` value passed in

Examples

Display fee before sending

import {
  calculateFeeForUserOperation,
  sendUserOperation,
} from '@dynamic-labs-sdk/zerodev';

const feeData = calculateFeeForUserOperation({
  userOperationData: {
    callGasLimit: 100_000n,
    verificationGasLimit: 50_000n,
    preVerificationGas: 21_000n,
    maxFeePerGas: parseGwei('30'),
  },
  networkData,
});

console.log(`This operation will cost ~${feeData.humanReadableAmount} ETH`);

const receipt = await sendUserOperation({ walletAccount, calls });

With USD conversion

import { calculateFeeForUserOperation } from '@dynamic-labs-sdk/zerodev';
const ETH_PRICE_USD = 3200;

const feeData = calculateFeeForUserOperation({
  userOperationData: {
    callGasLimit: 100_000n,
    verificationGasLimit: 50_000n,
    preVerificationGas: 21_000n,
    maxFeePerGas: parseGwei('50'),
  },
  networkData,
  nativeTokenPriceUsd: ETH_PRICE_USD,
});

console.log(`Fee: ${feeData.humanReadableAmount} ETH ≈ $${feeData.usdAmount}`);

Error handling

import { calculateFeeForUserOperation } from '@dynamic-labs-sdk/zerodev';
import { FeeEstimationFailedError } from '@dynamic-labs-sdk/client';

try {
  const feeData = calculateFeeForUserOperation({ userOperationData, networkData });
} catch (error) {
  if (error instanceof FeeEstimationFailedError) {
    console.error('Fee calculation failed:', error.message);
  }
}

estimateUserOperationGas - Estimate gas cost for a user operation (makes network calls)
simulateZerodevUserOperation - Full simulation with asset diffs and security validation
sendUserOperation - Send a user operation
calculateEvmTransactionFee - Fee estimation for standard EVM transactions
getNetworksData - Get network configuration objects

​Installation

​Usage

​Parameters

​Returns

​Examples

​Display fee before sending

​With USD conversion

​Error handling

​Related functions