eth_feeHistory

Returns historical gas data for a contiguous range of blocks, including per-block base fees and the distribution of priority fees. Useful for building EIP-1559 fee-estimation strategies.

Parameters

Position	Name	Type	Description
1	blockCount	string | number	Number of blocks to return. Decimal or hexadecimal integer. The maximum is typically 1024. Required.
2	newestBlock	string	The highest block to include, as a block number in hex or a block tag ("latest", "pending", etc.). Required.
3	rewardPercentiles	array	Array of percentile values (0–100) to sample from each block’s priority fees. For example, [25, 50, 75] returns the 25th, 50th, and 75th percentile priority fees. Required.

Returns

result (object):

Field	Type	Description
oldestBlock	string	The oldest block number in the result set (hex).
baseFeePerGas	array	Base fees per gas for each block, plus one extra entry for the next pending block.
gasUsedRatio	array	Gas-used to gas-limit ratios for each block (0.0 to 1.0).
reward	array	Two-dimensional array of priority-fee percentiles per block, matching the requested percentile values.

Example

Request

{
  "jsonrpc": "2.0",
  "method": "eth_feeHistory",
  "params": ["0xa", "latest", [25, 50, 75]],
  "id": 1
}

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "oldestBlock": "0x158a0e0",
    "baseFeePerGas": ["0xf5", "0xf7", "0xfa", "0xfc", "0xf8", "0xf5", "0xf2", "0xf0", "0xef", "0xf1", "0xf3"],
    "gasUsedRatio": [0.45, 0.62, 0.38, 0.71, 0.55, 0.49, 0.43, 0.37, 0.52, 0.64],
    "reward": [
      ["0x1", "0x1", "0x2"],
      ["0x1", "0x1", "0x1"]
    ]
  }
}