epoch & timestamp converter
Paste a Unix timestamp, an ISO 8601 string, or any moment a browser understands. It reads back as epoch seconds and milliseconds, ISO 8601 in UTC, RFC 2822, your local time, a few common timezones, and how long ago it was. Seconds versus milliseconds is auto-detected. It runs entirely in your browser, so it works offline and nothing is sent anywhere.
What it accepts
| Input | Read as |
|---|---|
| 1750000000 | 10-digit integer → epoch seconds. Anything 12 digits or longer is read as milliseconds; 11 digits is ambiguous and treated as seconds (year ~5138 is the tell). |
| 1750000000000 | 13-digit integer → epoch milliseconds. |
| 1750000000.5 | a decimal point means fractional seconds. |
| 2026-06-22T18:00:00Z | ISO 8601 with a Z or offset is exact. Without one, it is read in your local zone. |
| 2026-06-22 | a bare date is midnight UTC, per the ISO date-only rule. |
| now | the current moment. The button does the same and keeps ticking until you type. |
The Unix epoch is 1970-01-01T00:00:00Z. Epoch seconds crossed 10 digits in 2001 and reach 11 digits in 2286; 32-bit signed time_t overflows on 2038-01-19T03:14:07Z (the value 2147483647). Negative timestamps are dates before 1970 and are handled.