# difficulty

Description: difficulty cheatcode documentation

Note: This document was authored using MDX

  Source: https://github.com/NomicFoundation/hardhat-website/tree/main/src/content/docs/docs/reference/cheatcodes/Environment/difficulty.mdx

{/* This document contains content copied/adapted from the Foundry Book (MIT licensed). See LICENSE in the parent directory. */}

### Signature

```solidity
function difficulty(uint256) external;
```

### Description

Sets `block.difficulty`.

If used with a post-merge EVM version (Paris and onwards), it will revert. In that case, use [`vm.prevrandao`][prevrandao] instead.

### Examples

```solidity
vm.difficulty(25);
emit log_uint(block.difficulty); // 25
```

[prevrandao]: /docs/reference/cheatcodes/environment/prevrandao