Time Duration

Duration units, not clock time

This page converts a length of time — how long something lasts — between seconds, minutes, hours, days, weeks, and years. It is not a clock or time-zone tool. For current local times around the world, use Time Zones. For days between two calendar dates, use Date Difference.

How the conversions are defined

Everyday duration maths uses fixed relationships for the smaller units and conventional averages for longer ones:

• 60 seconds = 1 minute
• 60 minutes = 1 hour
• 24 hours = 1 day
• 7 days = 1 week
• 1 year is treated as 365.25 days (average including leap years)

Those year and day conventions are suitable for rough planning and homework-style conversions. They are not civil-calendar rules that know which months have 28–31 days.

Worked example

A film lasting 150 minutes is 2.5 hours or 9,000 seconds. A project estimate of 3 weeks is 21 days or 504 hours. One year on this page is 365.25 days, about 52.179 weeks.

When this tool helps

Use it to translate bake timers, workout intervals, podcast lengths, SLA downtimes, or study blocks into another unit. Avoid using it as a birthday calculator or payroll calendar — those need actual dates.

Common mistakes

• Expecting months as a field — months vary from 28 to 31 days, so they are a poor fixed unit here.
• Confusing duration with time of day (14:30 vs 14.5 hours).
• Using 365 days for every year when leap-year average matters over long spans.

FAQs

Why 365.25 days per year?

It approximates the mean Gregorian year length so multi-year durations stay reasonable without a full calendar engine.

Can I convert workweeks of 5 days?

Not as a separate unit here — convert total days or hours for the span you care about.

Related: Date Difference, Time Zones.