Guide
Work with timestamps and time zones
Server logs, APIs and database rows rarely store local time: they store an instant, often as Unix seconds. This workflow shows how to read that instant, turn it into a wall-clock time for a specific place, and check a span of dates.
Step 1 — turn the number into an instant
The Unix Timestamp Converter accepts seconds or milliseconds and can detect the unit automatically. It shows the UTC instant, a human-readable UTC string and a chosen time zone side by side.
Input
1700000000 (seconds)
Output
2023-11-14T22:13:20.000Z 2023-11-14 22:13:20 UTC 2023-11-14 17:13:20 in America/New_York (UTC-05:00)
The ten-versus-thirteen digit trap is real: 1700000000 is 2023, while
1700000000000 is the same moment in milliseconds. Auto-detect treats values
of 1,000,000,000,000 or more as milliseconds.
Step 2 — see a wall-clock time in other zones
A timestamp is unambiguous, but a meeting time is not: 09:00 only means something with a place attached. The Time Zone Converter reads a date and time in one IANA zone and shows the same moment in every other zone in the list, applying the daylight-saving rules for that specific date.
Input
2024-01-31 09:00 in America/New_York
Output
America/New_York 2024-01-31 09:00 UTC-05:00 Europe/London 2024-01-31 14:00 UTC+00:00 Asia/Tokyo 2024-01-31 23:00 UTC+09:00 UTC instant: 2024-01-31T14:00:00.000Z
The offset is date-specific. The same 09:00 on 2024-07-31 is still 14:00 in London but 22:00 in Tokyo, because New York observes daylight saving and Japan does not. A time that crosses midnight is flagged as next day so it is not mistaken for the same date.
Step 3 — check a span of dates
Once the instants are clear, the Date Difference Calculator measures the distance between two dates as calendar days, business days and a duration. For a deadline that skips weekends or holidays, use the Business Days Calculator instead.
Input
Start: 2026-01-01 End: 2026-01-31
Output
30 calendar days 22 business days 8 weekend days
Common mistakes
- Reading a millisecond timestamp as seconds, which lands roughly 50,000 years early.
- Assuming a fixed offset such as UTC-5 all year, without checking the date for daylight saving.
- Treating abbreviations such as EST as portable; prefer full IANA names like America/New_York.
Tools in this workflow
- Unix Timestamp Converter — epoch to date and back.
- Time Zone Converter — one instant in many zones.
- Date Difference Calculator — days between two dates.
- Business Days Calculator — weekends and holidays.