# Get the day of the year from a date

Count days from January 1, which is day 1.

Canonical: https://1loc.dev/date-time/get-the-day-of-the-year-from-a-date/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function dayOfYear(date) { return Math.round((Date.parse(date) - Date.parse(`${date.slice(0, 4)}-01-01`)) / 86400000) + 1; }
```

## Input

```json
"2026-10-28"
```

## Expected output

```json
301
```

## Edge case

Input:
```json
"2024-12-31"
```
Output:
```json
366
```

## Limits

- UTC dates, so daylight-saving changes cannot shift the count; the original subtracted local Date objects.

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/get-the-day-of-the-year-from-a-date.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: Uses UTC dates so daylight saving cannot shift the count. Original MDX retained as inert source evidence.