# Truncate a number at decimal

Drop the fractional part toward zero.

Canonical: https://1loc.dev/number/truncate-a-number-at-decimal/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function truncate(n) { return Math.trunc(n); }
```

## Input

```json
12.75
```

## Expected output

```json
12
```

## Edge case

Input:
```json
-12.75
```
Output:
```json
-12
```

## Limits

- The original ~~n only works within 32 bits: ~~3000000000 is -1294967296. Math.trunc works for every number.

The lab validates types and size before calling this function. Add equivalent validation at your own trust boundary.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/truncate-a-number-at-decimal.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: onelifemedia
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Uses Math.trunc; the original ~~n wrapped numbers beyond 32 bits. Original MDX retained as inert source evidence.