Unix Timestamp Converter — Epoch ↔ Readable Time
Convert Unix timestamps to UTC and local datetimes, or pick a local datetime to get epoch seconds or milliseconds. Steps: paste a timestamp or choose a date, pick seconds or milliseconds, then copy. Example: 1516239022 → 2018-01-18T01:30:22.000Z plus your local equivalent. Nothing is uploaded.
How it works
Timestamp → Date: paste a numeric epoch; we detect seconds vs milliseconds when possible and show UTC ISO time plus a local formatted string. Date → Timestamp: pick a datetime-local value (interpreted in your browser timezone) and output seconds or milliseconds. All conversion stays local.
Rules you should expect
Rules for epoch values, unit detection, timezone interpretation, and safe numeric limits.
- Epoch zero is 1970-01-01T00:00:00.000Z. Negative timestamps are before 1970. Seconds fit in ~10 digits; milliseconds need ~13.
- Auto-detect: ≥13 digits or absolute value >1e12 → milliseconds; ≤10 digits → seconds. You can override with the unit toggle.
- datetime-local input has no timezone suffix — the browser treats it as local wall time. UTC output always uses ISO 8601 with Z.
- Privacy: no upload. Uses native Date and Intl only. For named time zones beyond local, see the timezone converter in Related tools when available.
Example
Timestamp → Date (seconds): 1516239022 → UTC 2018-01-18T01:30:22.000Z and your browser local time. Date → Timestamp: pick 2018-01-18 09:30 local → seconds or ms per unit toggle.
Good fits
- Developers: decode epoch values from API responses, webhooks, or server logs.
- JWT debugging: convert exp / iat numeric claims to readable dates (pair with JWT decoder).
- Ops / analytics: quickly check whether a 10- or 13-digit field is seconds or milliseconds.
Frequently asked questions
Seconds or milliseconds?
Unix time is usually seconds since 1970-01-01 UTC. JavaScript and many APIs use milliseconds (13 digits). Ten-digit values are treated as seconds; thirteen-digit (or >1e12) values auto-switch to milliseconds.
What is the difference between UTC and local?
UTC is the same instant worldwide (ISO 8601 with Z). Local uses your browser timezone and locale formatting — handy when logs show UTC but you think in local time.
What does the Now button do?
Now fills the current epoch value (seconds or ms per your unit toggle) or the current local datetime, then converts immediately.
Are there range limits?
JavaScript Date supports roughly ±100 million years in milliseconds. Values outside that range show an error instead of a wrong date.
Related tools
Questions or feedback
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