estimateFeesPerGas ​

Returns an estimate for the fees per gas (in wei) for a transaction to be likely included in the next block.

If chain.fees.estimateFeesPerGas is set on the Client Chain or override Chain, it will use the returned value.

Otherwise, for EIP-1159 Transactions, viem will estimate the fees using a combinaton of the block's base fee per gas (to derive maxFeePerGas) + the estimateMaxPriorityFeePerGas Action (to derive maxPriorityFeePerGas). For Legacy Transactions, viem will estimate the fee based on the gas price (via the getGasPrice Action).

Usage ​

import { publicClient } from './client'

const {
  maxFeePerGas,
  maxPriorityFeePerGas
} = await publicClient.estimateFeesPerGas()
/**
 * {
 *   maxFeePerGas: 15_000_000_000n,
 *   maxPriorityFeePerGas: 1_000_000_000n,
 * }
 */

const { gasPrice } = await publicClient.estimateFeesPerGas({
  type: 'legacy'
})
/** 
 * { gasPrice: 15_000_000_000n } 
 */

import { createPublicClient, http } from 'viem'
import { mainnet } from 'viem/chains'

export const publicClient = createPublicClient({
  chain: mainnet,
  transport: http()
})

Returns ​

FeeValues

An estimate (in wei) for the fees per gas.

Parameters ​

chain (optional) ​

• Type: Chain
• Default: client.chain

Optional Chain override. Used to infer the fees per gas from chain.fees.estimateFeesPerGas.

import { optimism } from 'viem/chains' 

const { maxFeePerGas, maxPriorityFeePerGas } = 
  await publicClient.estimateFeesPerGas({
    chain: optimism 
  })

type (optional) ​

• Type: "legacy" | "eip1559"
• Default: "eip1559"

const { gasPrice } = await publicClient.estimateFeesPerGas({
  type: 'legacy' 
})