Time Duration Calculator
The exact time between two dates and times in days, hours, minutes and total seconds, plus the working hours it covers under your own working-day definition.
Time Duration Calculator: with the default inputs, duration is 7 days, 8 hours, 30 minutes.
24-hour clock: 0 is midnight, 13 is 1 pm.
- Total days
- 7.35417
- Total hours
- 176.5
- Total minutes
- 10,590
- Total seconds
- 635,400
- Business hours
- 48Only the parts of the span that fall inside a working day.
- Equivalent working days
- 6
- Calendar days touched
- 8
Assumptions
- A day is exactly 24 hours and a week exactly 168; leap seconds and daylight saving are outside this timeline.
- Business hours use one continuous window per working day, with no public holidays and no breaks.
- Both times are read on the same clock — convert time zones before entering them if the ends are in different zones.
| Unit | Amount |
|---|---|
| Weeks | 1.0506 |
| Days | 7.3542 |
| Hours | 176.5 |
| Minutes | 10,590 |
| Seconds | 635,400 |
Weeks and days here are exactly 7 × 24 h and 24 h. Calendar months and years are not fixed lengths, so they are deliberately not listed.
How this is worked out
The formula
Both points are reduced to a whole number of minutes since 1970-01-01 00:00: minutes = (days since the epoch × 1440) + hour × 60 + minute duration = end − start (exact integer arithmetic, no rounding) days = ⌊duration ÷ 1440⌋ hours = ⌊(duration mod 1440) ÷ 60⌋ mins = duration mod 60 Business hours: for each calendar day the span touches, take the overlap between [start, end] and that day's [open, close] window, skipping non-working weekdays, and add the overlaps up.
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Start date
- A calendar date.defaults to today
- Start hour
- 24-hour clock: 0 is midnight, 13 is 1 pm.from 0 to 23 · whole numbers only · defaults to 9
- Start minute
- A number.from 0 to 59 · whole numbers only · defaults to 0
- End date
- A calendar date.defaults to today+7
- End hour
- A number.from 0 to 23 · whole numbers only · defaults to 17
- End minute
- A number.from 0 to 59 · whole numbers only · defaults to 30
- Working day starts at(under More options)
- Used only for the business-hours figure.from 0 to 23 · whole numbers only · defaults to 9
- Working day ends at(under More options)
- 24 means midnight at the end of the day.from 1 to 24 · whole numbers only · defaults to 17
- Saturday is a working day(under More options)
- Turn this on or off.defaults to off
- Sunday is a working day(under More options)
- Turn this on or off.defaults to off
What you get back
- Durationmain answer
- Total days
- Total hours
- Total minutes
- Total seconds
- Business hours
- Only the parts of the span that fall inside a working day.
- Equivalent working days
- Calendar days touched
What this assumes
- A day is exactly 24 hours and a week exactly 168; leap seconds and daylight saving are outside this timeline.
- Business hours use one continuous window per working day, with no public holidays and no breaks.
- Both times are read on the same clock — convert time zones before entering them if the ends are in different zones.
About this calculator
Two moments in time, and the exact gap between them: days, hours and minutes, plus the totals in every single unit, plus how much of that gap was actually working time.
How to enter the times
Give each end a date and a time on the 24-hour clock — 0 is midnight, 13 is 1 pm. The arithmetic is done in whole minutes since a fixed epoch, so nothing is rounded and nothing depends on the time zone your browser happens to be in. If you put the end before the start, the calculator shows the gap anyway and says it has done so.
Business hours
The business-hours figure is the part of the span that falls inside a working day. Open "More options" to set when your working day starts and ends and whether weekends count. The calculator then walks the span one calendar day at a time and adds up the overlap between your span and that day's open window — so a Friday 4 pm to Monday 10 am gap comes out as two working hours under a 9-to-5 Monday-to-Friday definition, not 66.
This is the number that support SLAs, legal deadlines and billing usually mean. Two things it deliberately does not know: public holidays, which vary by country, state and company and would need a maintained table to be honest about; and anything other than a single continuous window per day, so a split shift with a two-hour lunch break needs the working day narrowed to compensate.
Days, hours, and what those words mean
A "day" here is exactly 24 hours and a "week" exactly 168, which is what you want for elapsed-time arithmetic. Calendar months and years are not fixed lengths — a month is anywhere from 28 to 31 days — so the unit table stops at weeks rather than pretending otherwise. If you want month or year arithmetic on whole dates, the date calculator does that properly.
Daylight saving is the other place a "day" stops being 24 hours: in a spring-forward local day there are only 23. This calculator works in a single continuous timeline, so if your two points straddle a clock change in a real time zone, the wall-clock difference and the elapsed time differ by an hour. Convert both ends with the time zone converter first if that matters.
Where the precision goes
Everything is integer minutes, so the totals are exact rather than accumulated floating-point sums. Total seconds are therefore always a whole number, and total days is that count divided by 1440 — the only place a fraction appears.
Frequently asked questions
▸How many hours are between two dates and times?
Take the total minutes between them and divide by 60. The calculator does this exactly in integer minutes, so a span of 7 days and 8.5 hours reads as 176.5 hours, not 176.4999.
▸What counts as a business hour here?
Any minute of the span that falls inside your defined working window on a working weekday. Weekends are excluded by default and can be switched on individually.
▸Does it know about public holidays?
No, deliberately. Holiday calendars differ by country, state and employer, and a hard-coded list would be wrong for most people. Subtract them yourself, or narrow the working days.
▸Why is a day exactly 24 hours here?
Because this is elapsed-time arithmetic on a single continuous timeline. Real local days can be 23 or 25 hours around a daylight-saving change; convert both endpoints first if your span crosses one.
▸Can the end be before the start?
Yes. The calculator reports the size of the gap and flags that the two are the wrong way round, rather than refusing or showing a negative day count.
Put this calculator on your own site
A working duration, free for any site, with no ads and no sign-up. It resizes to fit wherever you paste it and updates itself as this page improves.
Paste this anywhere. It works on any site, carries no ads, never expires, and always shows the current version.
Time Duration Calculator by CalculateItNow
The page's own title. The clearest description of what the link leads to.
The credit line sits outside the widget on purpose, so it is a real link on your page rather than one buried in a frame. Please keep it — it is what pays for CalculateItNow staying free and ad-free. The script only resizes the widget to fit its contents; drop it and the widget still works.
Browse every calculator widget·How to add it to WordPress, Squarespace or Wix
Related calculators
The questions people ask next to a duration.
Timesheet calculator: hours worked between start and end times minus breaks, per day, week and pay period, with gross pay. Handles overnight shifts.
Count the days, weeks, months and business days between two dates, or add and subtract days, weeks, months or years from any date — leap years handled exactly.
Add or subtract two durations in hours, minutes and seconds and get the result as h:mm:ss, decimal hours, total minutes and total seconds — with the carrying shown.
What day of the week a date falls on, plus its day number in the year, ISO week number, leap-year status, and that date's weekday in nearby years.
Convert a date and time between world time zones using real IANA zone data, so daylight saving is applied correctly rather than a fixed, half-wrong offset.
Find your exact age in years, months and days, total days and weeks lived, your next birthday, the day of the week you were born and your zodiac sign.