Convert between milliseconds, seconds, minutes, hours, days, weeks and years. Useful for project timelines, countdowns and any calculation involving durations.
Quick reference
- 1 minute = 60 seconds
- 1 hour = 3,600 seconds
- 1 day = 86,400 seconds
- 1 week = 168 hours
- 1 year (365 days) = 8,760 hours
Simple as time conversion sounds, it’s easy to make an arithmetic slip converting large numbers of seconds into days or weeks by hand — this calculator does it instantly and exactly.
How to convert time units
Time units use fixed multiples: 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day and 7 days in a week. A year in this converter is a calendar year of 365 days.
Example: how long is a million seconds? 1,000,000 ÷ 86,400 seconds per day = 11.57 days.
Frequently asked questions
Why aren’t months included?
Months vary from 28 to 31 days, so there is no exact conversion. For the same reason, the year here is fixed at 365 days; a leap year has 366, and the average calendar year is 365.2425 days.
How many hours are in a week?
168 hours (7 days × 24 hours).
How many seconds are in a day?
86,400 seconds (24 × 60 × 60).