# eth_feeHistory: parameters, returns and CU

> Original page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_feeHistory/

## Summary

Return historical base fees, gas usage ratios and optional priority-fee percentiles over a range of blocks.

## Compute Units (CU) and Pricing

CU weight, price and per-chain availability are shown on the method page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_feeHistory/

## Parameters

| Parameter | Type | Description |
| --- | --- | --- |
| `blockCount` | `QUANTITY` | Number of blocks to query, as a 0x-prefixed hexadecimal quantity. |
| `newestBlock` | `QUANTITY\|TAG` | Newest block in the range, as a block number or tag such as latest. |
| `rewardPercentiles` | `ARRAY` | Optional ascending array of percentiles between 0 and 100, used to compute priority-fee percentiles per block. |

## Returns

- **Type**: `object`
- **Description**: Object with oldestBlock, baseFeePerGas (an array one longer than blockCount), gasUsedRatio, and, when rewardPercentiles is given, a two-dimensional reward array.

## Notes

This is the EIP-1559 fee-history method; when rewardPercentiles is omitted, the result has no reward field.

## Request Example

```bash
curl -X POST "https://dev-api.blockvectra.network/v1/robinhood_mainnet" \
  -H 'Content-Type: application/json' \
  -H 'x-api-key: <api_key>' \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_feeHistory",
    "params": [
      "<blockCount>",
      "latest",
      []
    ],
    "id": 1
  }'
```