# Time Duration Calculator Last updated October 17, 2026FreeNo signupFormula shown Enter a start and an end date and time, and this time duration calculator gives the time between them in hours and minutes, in days and in decimal hours. Pick a time zone and it counts the daylight saving changes too, or switch modes to add or subtract time. What do you need? Between two timesAdd or subtract Start date Start time End date End time Time zoneNo time zone (every day is 24 hours)Eastern Time (ET)Central Time (CT)Mountain Time (MT)Arizona (Mountain, no daylight saving)Pacific Time (PT)Alaska Time (AKT)Hawaii Time (HT)Atlantic Time (AT)Coordinated Universal Time (UTC) Picks up the daylight saving changes of that zone. No time zone counts every day as 24 hours. Time between 32 h 30 min 1 day, 8 hours, 30 minutes From Mon, Nov 2, 2026, 10:00 PM ESTto Wed, Nov 4, 2026, 6:30 AM EST teampredict.ai/tools/time-duration-calculator The span, every way Decimal hours 32.5 Total minutes 1,950 Days, hours and minutes 1 d 8 h 30 min Clock changes None in this span Eastern Time (ET) Copy resultsCopy link ## A time duration is the end time minus the start time, across as many days as it takes. Duration = end date and time − start date and time The calculator puts both moments on one timeline and subtracts. The answer comes four ways: hours and minutes, days, hours and minutes, decimal hours and total minutes. Because each time carries its own date, a span can run past midnight, past a weekend or past a month end without any guessing about which day the end belongs to. If the end comes before the start, the calculator counts from the earlier one and says so. The time zone menu decides how long a day is. With a US zone picked, the calculator follows that zone's daylight saving rules, so a span that crosses a clock change comes out an hour longer or shorter. With “No time zone” every day is exactly 24 hours, which is plain clock arithmetic. ## Monday at 10:00 PM to Wednesday at 6:30 AM is 32 hours and 30 minutes. Those are the times the calculator opens with: an invented on-call stretch in Eastern time that starts on Monday, November 2, 2026 at 10:00 PM and ends on Wednesday, November 4 at 6:30 AM. - Monday, 10:00 PM to midnight: 2 hours - Tuesday, midnight to midnight: 24 hours - Wednesday, midnight to 6:30 AM: 6 hours 30 minutes - Total: 32 hours 30 minutes, which is 1 day, 8 hours and 30 minutes - In decimal hours: 32 + 30 ÷ 60 = 32.5, or 1,950 minutes _Figure: Timeline of the worked example, an invented on-call stretch in Eastern time. Monday, November 2, 2026 from 10:00 PM to midnight is 2 hours. All of Tuesday, November 3 is 24 hours. Wednesday, November 4 from midnight to 6:30 AM is 6 hours 30 minutes. Together that is 32 hours 30 minutes, which is 32.5 decimal hours, 1,950 minutes, or 1 day, 8 hours and 30 minutes._ No clock change falls inside this stretch, because in 2026 the clocks go back on Sunday, November 1, the day before it starts. Switch to “Add or subtract” and the same start runs the other way: 8 hours 30 minutes after Monday at 10:00 PM is Tuesday, November 3 at 6:30 AM. ## Two days a year are not 24 hours long in most of the United States. Federal law, [15 U.S.C. 260a](https://www.law.cornell.edu/uscode/text/15/260a), moves standard time forward an hour from 2 a.m. on the second Sunday of March to 2 a.m. on the first Sunday of November. [NIST](https://www.nist.gov/pml/time-and-frequency-division/popular-links/daylight-saving-time-dst), the national timekeeper, gives the 2026 dates as March 8 and November 1. On March 8 the local time skips from 2 a.m. to 3 a.m., “so there is one less hour in that day.” On November 1, 2 a.m. becomes 1 a.m. again “and that hour is repeated.” Midnight to midnight, the first day lasts 23 hours and the second 25. _Figure: A chart of 2026 in a US time zone that observes daylight saving time. Daylight saving time runs from March 8 at 2 a.m. to November 1 at 2 a.m., 238 days or about 65% of the year, according to NIST. Sunday, March 8, 2026 has 23 hours because 2 a.m. becomes 3 a.m. Sunday, November 1, 2026 has 25 hours because 2 a.m. becomes 1 a.m. and that hour repeats. Every other day has 24 hours._ NIST puts daylight saving time at 238 days, about 65% of the year. The same rule sets the 2027 changes for March 14 and November 7. Hawaii, Puerto Rico, the Virgin Islands, Guam, American Samoa and most of Arizona keep standard time all year, so picking Arizona or Hawaii in the menu gives 24-hour days every day. The change nights also create clock times that do not exist or happen twice. 2:30 AM on March 8, 2026 never appears on a clock in Eastern time, so the calculator reads it as 3:30 AM and says so. 1:30 AM on November 1 happens twice, and the calculator uses the first one, still on daylight time, and names it under the result. ## The night the clocks go back, an eight-hour overnight shift is nine hours of work. The Department of Labor's [Hours Worked Advisor](https://webapps.dol.gov/elaws/whd/flsa/hoursworked/screenER11.asp) uses a shift that starts at 11:00 p.m. and ends at 7:30 a.m. the next day with a 30-minute lunch, eight hours of work. On the night daylight saving time begins, the employee works 7 hours. On the night it ends, the hour from 1:00 a.m. to 2:00 a.m. is worked twice, so the shift is 9 hours. The Department's rule is plain: “The FLSA requires that employees must be credited with all of the hours actually worked.” _Figure: The Department of Labor's example shift runs from 11:00 p.m. to 7:30 a.m. with a 30-minute lunch, eight hours of work. On the night daylight saving time begins, March 7 to 8, 2026, it is 7 hours 30 minutes on the clock and 7 hours worked. On any other night it is 8 hours 30 minutes on the clock and 8 hours worked. On the night daylight saving time ends, October 31 to November 1, 2026, it is 9 hours 30 minutes on the clock and 9 hours worked._ The calculator gets the same answer. From Saturday, October 31, 2026 at 11:00 PM to Sunday, November 1 at 7:30 AM in Eastern time it shows 9 hours 30 minutes on the clock, which is 9 hours after the lunch. From March 7 to March 8 it shows 7 hours 30 minutes. With “No time zone” both nights show 8 hours 30 minutes, which is the schedule rather than the hours worked. This matters to more people than it seems: the [BLS](https://www.bls.gov/news.release/flex2.nr0.htm) found that 14.8% of wage and salary workers usually worked something other than a regular daytime schedule in 2024 and 2025, and 3.4% worked nights. The [time card calculator](https://www.teampredict.ai/tools/time-card-calculator) adds up a week of such shifts. ## A workweek under federal law is a fixed block of 168 hours. Overtime is counted per workweek, and [29 CFR 778.105](https://www.ecfr.gov/current/title-29/section-778.105) defines one as “a fixed and regularly recurring period of 168 hours,” or “seven consecutive 24-hour periods.” It “need not coincide with the calendar week but may begin on any day and at any hour of the day,” and once set it stays fixed whatever hours are worked. _Figure: A grid of 168 hours, seven rows of 24, for a workweek that starts on Monday at 10:00 PM and ends the next Monday at 10:00 PM. Federal rules let a workweek start on any day and at any hour. The worked example's on-call stretch, 32.5 hours, fills the first row and the first 8.5 hours of the second, up to 6:30 AM on Wednesday, about 19% of the week._ A workweek that starts on Monday, November 2, 2026 at 10:00 PM ends 168 hours later, on Monday, November 9 at 10:00 PM, which is what the calculator shows when you add 168 hours or 7 days to that start. The worked example's on-call stretch takes up the first 32.5 hours of that week, about 19% of it. Once the hours worked in a workweek pass 40, the [overtime calculator](https://www.teampredict.ai/tools/overtime-calculator) works out time and a half. ## Decimal hours turn a duration into something payroll can multiply. Minutes are sixtieths of an hour, so 32 hours 30 minutes is 32.5 hours, not 32.30. At an invented rate of $20 an hour the right figure pays $650.00 and the wrong one $646.00, a gap of 12 minutes of pay. The [hours calculator](https://www.teampredict.ai/tools/hours-calculator) has a full table of minutes in decimal, and works one shift at a time with an unpaid break taken off. Midnight needs care at either end of a span. NIST's [times of day FAQ](https://www.nist.gov/pml/time-and-frequency-division/times-day-faqs) says “12 a.m. and 12 p.m. are ambiguous and should not be used,” and suggests 11:59 p.m. or 12:01 a.m. for deadlines. The [military time converter](https://www.teampredict.ai/tools/military-time-converter) writes the same moment as 0000 or 2400. For whole days rather than hours, the [days between dates calculator](https://www.teampredict.ai/tools/days-between-dates-calculator) counts them and the [date calculator](https://www.teampredict.ai/tools/date-calculator) adds them to a date. When the start and the end are in different time zones, convert one into the other first with the [time zone converter](https://www.teampredict.ai/tools/time-zone-converter). ## A duration shows how long someone worked, not how long they will stay. Every number on this page measures time already spent: a shift, an on-call stretch, a workweek. None of them says who on the team is about to stop spending it with you. TeamPredict works on that part, reading public LinkedIn signals to flag resignation risk early, so the first sign of a departure is a warning while there is still time to talk, rather than a rota with a gap in it. ## Methodology & sources The formula this calculator uses is shown in full above, and every assumption is an input you control. There are no hidden industry presets. All math runs in your browser; nothing you enter is stored or sent to a server. For the reasoning behind the formula and its edge cases, see: - [NIST: Daylight saving time (the 2026 dates and the length of the period)](https://www.nist.gov/pml/time-and-frequency-division/popular-links/daylight-saving-time-dst) - [15 U.S.C. 260a: Advancement of time (the second Sunday of March and first Sunday of November)](https://www.law.cornell.edu/uscode/text/15/260a) - [U.S. Department of Labor, FLSA Hours Worked Advisor: Daylight Savings Time](https://webapps.dol.gov/elaws/whd/flsa/hoursworked/screenER11.asp) - [29 CFR 778.105: Determining the workweek](https://www.ecfr.gov/current/title-29/section-778.105) - [BLS: Job Flexibilities and Work Schedules, 2024-2025 (shift usually worked)](https://www.bls.gov/news.release/flex2.nr0.htm) - [NIST: Times of day FAQs (noon and midnight)](https://www.nist.gov/pml/time-and-frequency-division/times-day-faqs) Embed this calculator Add the Time Duration Calculator to your own site, blog post, or internal wiki. It's free. 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``` Copy embed codeFree to embed. Please keep the attribution link. ## Frequently asked questions How do I calculate the time between two dates and times? Subtract the start from the end, counting each whole day in between as 24 hours unless a clock change falls inside it. Monday, November 2, 2026 at 10:00 PM to Wednesday, November 4 at 6:30 AM is 2 hours on Monday, 24 on Tuesday and 6 hours 30 minutes on Wednesday: 32 hours 30 minutes, or 32.5 hours. Pick a time zone in the calculator and it adds or takes away the daylight saving hour for you. How many hours are in a week? 168: seven days of 24 hours. The federal overtime rules use the same number and define a workweek as a fixed and regularly recurring period of 168 hours, which can start on any day and at any hour. A calendar week that contains the November clock change lasts 169 hours in most of the United States, and the week of the March change lasts 167. How do I add hours to a time? Add the hours and minutes to the clock time and carry into the next day each time you pass midnight. 8 hours 30 minutes after 10:00 PM on Monday, November 2, 2026 is 6:30 AM on Tuesday, November 3. In the calculator, choose Add or subtract: days move the date and keep the clock time, and hours and minutes are counted as they pass, so a clock change in between is handled. Does daylight saving time change how long a shift is? Yes, for a shift that runs through 2 a.m. on a change night. The Department of Labor's example is an 11:00 p.m. to 7:30 a.m. shift with a 30-minute lunch: 8 hours on a normal night, 7 hours worked on the night daylight saving time begins and 9 on the night it ends, and the employee has to be credited with all of the hours actually worked. In 2026 those nights end on March 8 and November 1. How do I turn hours and minutes into decimal hours? Divide the minutes by 60 and add the result to the hours. 32 hours 30 minutes is 32 + 30 ÷ 60 = 32.5 hours, and 9 hours 45 minutes is 9.75 hours. The calculator shows every duration in decimal hours and in total minutes, so either one can go straight into a timesheet. ## Turnover is cheaper to prevent than to calculate. TeamPredict flags resignation risk early from public LinkedIn signals, giving you lead time to retain your best people before they hand in notice. [Start 30-Day Free Trial](https://app.teampredict.ai/signup) No charge today · Cancel anytime ## Keep reading [Hours Calculator Hours and minutes between a start and an end time on one shift, less an unpaid lunch, in decimal hours. Read more](https://www.teampredict.ai/tools/hours-calculator) [Time Card Calculator A full workweek of clock-in and clock-out times, with breaks, the weekly total and overtime after 40 hours. Read more](https://www.teampredict.ai/tools/time-card-calculator) [Overtime Calculator Time and a half after 40 hours in a workweek, with the regular rate worked out when a bonus is paid. Read more](https://www.teampredict.ai/tools/overtime-calculator)