# Round to a number of digits

Apply decimal scaling and JavaScript rounding for display-oriented values.

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

## Implementation

```javascript
function roundTo({ value, digits }) { const factor = 10 ** digits; return Math.round(value * factor) / factor; }
```

## Input

```json
{
  "value": 12.3456,
  "digits": 2
}
```

## Expected output

```json
12.35
```

## Edge case

Input:
```json
{
  "value": 1.005,
  "digits": 2
}
```
Output:
```json
1
```

## Limits

- Binary floating-point explains the 1.005 edge case. This is not exact decimal arithmetic.
- The lab allows 0–6 digits. Never use this function as a financial rounding policy.

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/round-a-number-to-a-given-number-of-digits.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Curated implementation; explicit input bounds, edge cases, local fixtures and rebuilt presentation. Original MDX retained as inert source evidence.