Time converter guide
The second is the SI base unit of time. Minutes, hours, 24-hour days, and seven-day weeks have fixed relationships in this duration calculator.
Calendar months do not all contain the same number of days. The mean Gregorian month and year options are explicit averages based on 365.2425 days per year; they are not calendar-date arithmetic.
How to convert duration units
- Enter the duration: Provide a finite, non-negative elapsed time.
- Choose the source: Select a fixed duration or an explicitly labeled calendar average.
- Choose the target: Select the destination or use Swap.
- Convert: Select Convert duration to calculate through seconds.
Formula and variables
Every selected duration is converted through seconds.
target duration = source duration × (seconds per source unit) ÷ (seconds per target unit)- tₛ — Source duration
- A finite, non-negative elapsed time.
- fₛ — Source factor
- Seconds represented by one source unit.
- fₜ — Target factor
- Seconds represented by one target unit.
Convert hours to minutes
Express 1 hour as a duration in minutes.
- Duration
- 1
- From
- h
- To
- min
- 1 h = 3600 s
- 3600 s ÷ 60 s/min
Result: 1 h = 60 min.
This relationship is fixed and does not depend on a calendar or time zone.
Understanding your results
Fixed durations
Nanoseconds through weeks use defined counts of seconds in this calculator.
Calendar averages
Mean Gregorian months, years, decades, and centuries are planning averages. Actual date spans must be calculated from calendar dates.
Assumptions
- One minute is 60 s, one hour is 3600 s, and one 24-hour day is 86,400 s.
- One week is seven 24-hour days.
- A mean Gregorian year is 365.2425 days.
- A mean Gregorian month is one twelfth of that mean year.
Limitations
- The calculator does not perform calendar-date arithmetic.
- It does not account for time zones, daylight-saving transitions, or leap seconds.
- A calendar month is not a fixed duration.
- Very large values can lose floating-point precision.
Common mistakes
- Treating every calendar month as the same number of days.
- Using an average year for an exact deadline.
- Mixing elapsed duration with clock time or time zone conversion.
- Ignoring daylight-saving changes in civil schedules.
- Rounding subsecond values before conversion.
Practical use cases
Elapsed-time calculations
Convert seconds, minutes, hours, days, or weeks for rates and schedules.
Approximate long-range planning
Use explicitly labeled mean Gregorian periods when an average duration is appropriate.
Planning and decision guide
Use dates for calendar commitments
For billing dates, anniversaries, deadlines, or age, compute between actual dates. Use the average month only when an average duration is genuinely intended.
Frequently asked questions
How many seconds are in one hour?
One hour contains exactly 3600 seconds.
How many seconds are in one day?
A 24-hour day contains 86,400 seconds.
Is a month a fixed number of seconds?
No. Calendar months vary; this calculator labels its month option as a mean Gregorian month.
What is a mean Gregorian year?
It is an average duration of 365.2425 days, derived from the Gregorian leap-year cycle.
Does this handle time zones or leap seconds?
No. It converts elapsed-duration units, not civil timestamps.
Sources and review
- NIST Guide to the SI, Appendix B.9: Time conversion factors — National Institute of Standards and Technology. Accessed 2026-08-30.
- SI Brochure, 9th edition — International Bureau of Weights and Measures. Accessed 2026-08-30.
Reviewed 2026-08-30.