Free · Time conversions

Duration in Hours, Weeks & Julian Years

Convert a duration between seconds, minutes, hours, days, weeks and fixed-length years, with compound time inputs.

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

8,766 hours equal 365.25 days, one Julian year, twelve model months or 31,557,600 seconds. A week is seven days; a model month is one twelfth of a Julian year.

1 week = 168 hours; 1 Julian year = 8,766 hours = 365.25 days; 1 model month = 730.5 hours

Worked example

Enter these known values and leave the other values blank.

Hours
8766 hrs
Weeks
52.18 wks
Julian years
1 yrs
Model months
12 mos
Days
365.25 days
Minutes
525960 min
Seconds
31557600 sec
Compound duration
8766:0:0 hrs / min / sec

Assumptions and limitations

  • This is an elapsed-duration conversion. Months use 30.4375 days and years use 365.25 days. Calendar months, calendar years, daylight-saving changes and leap seconds require date/time arithmetic instead.
  • A colon separates compound units: 1:30:0 means one hour thirty minutes in the hours/minutes/seconds field. Decimal 1.5 hours represents the same duration.

Common questions

Why is one month longer than four weeks?

Four weeks are 28 days. This model divides a 365.25-day Julian year into twelve equal 30.4375-day months. Actual calendar months contain 28–31 days.

Can this calculate a calendar deadline?

No. It converts a supplied duration. A deadline requires a starting date, calendar rules and, when relevant, a time zone.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

Explore time conversions or browse all conversion calculators.