Timestamp Cheatsheet
A compact reference for common timestamp formats and conversion patterns.
Common formats
- Unix seconds: 10 digits (e.g. 1716547200)
- Unix milliseconds: 13 digits (e.g. 1716547200000)
- ISO 8601 UTC: 2026-05-24T06:00:00Z
- RFC 2822: Sun, 24 May 2026 06:00:00 GMT
Examples
- seconds to ISO: new Date(seconds * 1000).toISOString()
- ms to seconds: Math.floor(ms / 1000)
- ISO to seconds: Math.floor(new Date(iso).getTime() / 1000)
Common mistakes
- Sending milliseconds to an API expecting seconds.
- Parsing local date strings without timezone info.
- Mixing UTC storage with local-time comparisons.
FAQ
- Why use a timestamp cheatsheet?
- It reduces context switching and helps teams avoid unit and timezone mistakes during development.
- Does this replace full docs?
- No. It is a quick operational reference, not a language-specific specification.