Timestamp Converter

What it does

Converts a Unix epoch timestamp into every date representation you normally need, all at once: epoch seconds, epoch milliseconds, ISO 8601 (UTC), an RFC-style UTC string, your local time, and a plain-English relative phrase (“3 min ago”, “in 2 day”). It converts in both directions - type an epoch number or pick a date and time from the local picker.

Enter any second-precision value (negatives included) and the six output rows update instantly; each row has its own copy button. The relative bucket rounds to seconds, minutes, hours, days, months, or years. 100% client-side, evaluated in your browser’s time zone.

How to use it

1. The tool opens on the current time. Type any epoch value in seconds into Epoch (seconds) - or click Now to snap back to the present.
2. Alternatively set the date and time with the Date (local) picker; the epoch value follows.
3. Read the six rows: Epoch (s), Epoch (ms), ISO 8601, UTC, Local, Relative.
4. Click Copy on any row to grab exactly that representation.
5. Share a specific timestamp by adding ?t=<epoch-seconds> to the URL (e.g. /tools/timestamp?t=1750000000) - the tool loads with that value.
6. Below the rows, the prompt bar copies a pre-filled AI prompt built from your live values - Humanize for a changelog or Convert to RFC 3339.

Examples

Verified by running the tool’s exact row computation on fixed inputs. The first four rows are timezone-independent:

Input 1750000000:
  Epoch (s)     1750000000
  Epoch (ms)    1750000000000
  ISO 8601      2025-06-15T15:06:40.000Z
  UTC           Sun, 15 Jun 2025 15:06:40 GMT

Input 0 (the epoch itself):
  ISO 8601      1970-01-01T00:00:00.000Z
  UTC           Thu, 01 Jan 1970 00:00:00 GMT

Input 1000000000:
  ISO 8601      2001-09-09T01:46:40.000Z
  UTC           Sun, 09 Sep 2001 01:46:40 GMT

The Local and Relative rows depend on the viewing machine. On a UTC+2 machine, 1750000000 renders as 6/15/2025, 5:06:40 PM local; its relative phrase at the time of writing is 1 yr ago. A future value such as 2000000000 renders as in 7 yr - the relative row recomputes on every render.

Good to know

• Private: everything is computed locally in your browser; nothing is sent to a server.
• The tool works in seconds. If you paste a millisecond value, divide by 1000 first (the Epoch (ms) row gives you the exact product back).
• Negative epochs are valid and land before 1970 (-86400 → 1969-12-31T00:00:00.000Z). Absurdly large values (beyond the JS date range, e.g. 1e15) make the date rows show -.
• The local picker sends the chosen wall-clock time through your current time-zone offset, so a shared ?t= link shows the same instant but a different local string per viewer.
• Relative phrases use fixed-length buckets (30-day months, 365-day years) - they are human labels, not calendar arithmetic.
• Related tools: Cron Expression Explainer, ULID Generator, UUID Generator