Time Converters & Date Calculators
Convert between seconds, minutes, hours, days, and weeks with exact constants. Plus calendar-accurate date tools for age, date differences, and duration calculations.
Age Calculator
DOB → years, months, days
Date Difference Calculator
Days between two dates
Add Days to Date
Date + N days
Time Duration Calculator
Add/subtract hh:mm:ss
Hours Calculator
Sum hours for timesheets
Core Time Conversions
Seconds → Minutes
1 minute = 60 seconds (exact)
Minutes → Seconds
1 minute = 60 seconds (exact)
Minutes → Hours
1 hour = 60 minutes (exact)
Hours → Minutes
1 hour = 60 minutes (exact)
Hours → Days
1 day = 24 hours (exact)
Days → Hours
1 day = 24 hours (exact)
Days → Weeks
1 week = 7 days (exact)
Weeks → Days
1 week = 7 days (exact)
Seconds → Hours
1 hour = 3,600 seconds (exact)
Hours → Seconds
1 hour = 3,600 seconds (exact)
Frequently Asked Questions
Why can't I convert months or years to exact seconds?
Months have 28–31 days and years have 365 or 366 days. They aren't fixed time units. Use the date calculators for calendar-accurate results.
How many seconds in a day?
Exactly 86,400 seconds (24 × 60 × 60).
How many weeks in a year?
About 52.14 weeks (365 ÷ 7). A year is not an exact number of weeks.
What is the SI unit of time?
The second (s), defined by the cesium-133 atomic clock.
How does the age calculator handle leap years?
It uses calendar dates, so Feb 29 birthdays are correctly handled on a per-year basis.
Can I calculate the difference between two dates?
Yes! Use our Date Difference Calculator to get the exact number of days, weeks, and calendar difference (years/months/days).