Time Units Converter
Convert a duration among milliseconds, seconds, minutes, hours, days, and weeks. A day is 86400 SI seconds. This is not a calendar, a time zone, or a Unix timestamp.
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How to convert hours into seconds
- Enter the duration. The form starts at 1 hour.
- Keep From as Hours and To as Seconds, or pick minutes, days, weeks, or milliseconds.
- Read the second total. One hour is 3600 s. One day on this page is 86400 s.
- Swap units to go from seconds back to hours. Clock math that needs HH:MM:SS lives on other pages.
SI second
Duration (not a date)
| Second | SI base unit of time |
|---|---|
| Minute | 1 min = 60 s |
| Hour | 1 h = 3600 s |
| Day | 1 d = 86400 s (SI day) |
| Week | 1 wk = 7 d = 604800 s |
| Millisecond | 1 ms = 0.001 s |
What this time converter does
This page converts a length of time, not a calendar date. Milliseconds, seconds, minutes, hours, days, and weeks scale by fixed integers. One day is 86400 seconds, the SI day of 24 hours of 3600 seconds. A week is seven of those days (604800 s). Daylight saving, leap seconds, and civil midnights do not appear.
Split a duration into clock fields on hours minutes seconds. Add or subtract two durations on time duration. Other dimensions sit on the unit converter.
Duration factors
Canonical unit is the second. Multiply hours by 3600, days by 86400, weeks by 604800, minutes by 60, and milliseconds by 0.001. The reverse divides. 36 hours is 1.5 days on this scale, even if those hours cross a DST change on a wall clock.
Duration versus dates and Unix time
Unix time counts seconds from 1970-01-01 UTC and still needs a timezone to become a clock. This converter never parses a timestamp. It also does not name weekdays. Use a date tool when you care which civil day a span lands on. Use HMS when you want 5400 s printed as 1:30:00.
When to convert time units here
Turn a lab run from hours into seconds, a video length from minutes into milliseconds, or a two-week span into hours. Keep payroll calendars, meeting planners, and epoch converters elsewhere.
What this page does not do
It does not apply DST. It does not skip leap seconds. It does not convert Unix timestamps. Invalid numbers show in the status line. Values stay in this browser.