Timestamp Converter
Translate between Unix epoch and ISO 8601 dates in real time. Paste seconds, milliseconds, or any parseable date string — the converter fills in every other format and shows day-of-year, weekday, and time-zone variants.
One instant, every format
Type a timestamp on either side — the converter fills in seconds, milliseconds, UTC, local time, and a handful of derived fields.
1700000000
ISO: 2023-11-14T22:13:20.000Z UTC: Tue, 14 Nov 2023 22:13:20 GMT Local: Wed Nov 15 2023 09:13:20 GMT+1100 Day: Tuesday (day 318 of 2023)
What you'll use this for
Logs, APIs, and database fields disagree on time format — converting between them is a daily developer chore.
Debugging logs
Translate 1700000000 stamps in CloudWatch / journalctl / Stackdriver to a readable date.
Database fields
Convert between MySQL DATETIME, PostgreSQL TIMESTAMPTZ, and epoch column types.
JWT & API tokens
Decode iat, exp, and nbf claims to a human-readable time.
Scheduling
Sanity-check cron expressions and reminder offsets against the actual wall clock.
How to convert timestamps
Paste a timestamp or date
Either field works — converting both ways. ISO accepts any string Date can parse.
Pick the unit
Auto-detect treats 13-digit numbers as milliseconds; force seconds or ms if needed.
Read the breakdown
Seconds, milliseconds, ISO, UTC, local, day-of-week and day-of-year update instantly.
Copy what you need
Use the per-row copy buttons or the full breakdown copy in the action bar.
Frequently asked questions
A Unix timestamp counts the number of seconds elapsed since 00:00:00 UTC on 1 January 1970 (the epoch), ignoring leap seconds. It's the canonical numeric time format on every Unix-derived system.
Both. The auto-detect mode treats numbers ≥ 10¹² as milliseconds (which is what JavaScript's Date.now() returns) and everything else as seconds.
Timestamps themselves are zone-independent — they describe an instant. The breakdown shows that instant in both UTC and your browser's local zone so you can sanity-check offsets.
JavaScript uses 64-bit floats for timestamps, so we're safe well past 2038. The 32-bit signed limit (2147483647) is January 19, 2038 — only relevant if your downstream system uses a 32-bit time_t.
No — like every Unix timestamp, leap seconds are silently absorbed. For sub-second-accurate scientific timekeeping use TAI or GPS time instead.
About Unix time
Unix time, also called POSIX time or epoch time, was introduced in the early 1970s as a simple monotonic seconds counter. Today it's the lingua franca of timestamps — logs, databases, JWTs, file systems, and almost every network protocol use it under the hood.
Common formats you'll encounter
- Seconds since epoch —
1700000000. The Unixtime_tdefault. - Milliseconds since epoch —
1700000000000. JavaScript'sDate.now(). - ISO 8601 —
2023-11-14T22:13:20Z. Human-readable, JSON-friendly. - RFC 7231 HTTP date —
Tue, 14 Nov 2023 22:13:20 GMT. Used in HTTP headers.