Calculate the time between two dates or times instantly. Free duration calculator: days, hours, minutes, seconds and business days. In-browser.
This time duration calculator works out the exact time between two dates, or between two times on the same day, and reports the answer four ways at once: as a compact d h m s string, and as decimal totals in days, hours, minutes, and seconds. It also counts the business days in the span. Enter a start date and time, enter an end date and time, and the result appears immediately—there is no submit button, no signup, and no server round trip. All arithmetic runs in your browser.
Beyond simple duration, the tool has four modes. Calculate Duration measures the gap between two moments. Add Time and Subtract Time shift a starting date forward or backward by a number of days, hours, minutes, and seconds to give you a resulting date and time. Convert Units takes a duration you already know and expresses it in every unit, which is the fastest way to answer questions such as “how many hours is 3 days and 14 hours?” or “how many seconds is 45 minutes?”
When you calculate the time between two dates, the result panel gives you several representations of the same span, because different tasks need different units.
| Output | Example for 2026-03-01 09:00 → 2026-03-14 17:30 |
|---|---|
| Compact duration | 13d 8h 30m |
| Total days (decimal) | 13.35 |
| Total hours (decimal) | 320.50 |
| Total minutes | 19,230.00 |
| Total seconds | 1,153,800 |
| Business days | 10 |
The decimal totals are what you paste into a timesheet, an invoice, or a spreadsheet. The compact form is what you paste into a ticket or a status update. A copy button next to the result puts the compact form on your clipboard in one click.
Alongside the raw duration, the tool counts business days by walking the calendar day by day from the earlier date to the later one and counting every day that is not a Saturday or a Sunday. The count is inclusive of both endpoint days. In the example above, 1 March to 14 March 2026 spans 14 calendar days, of which 10 are weekdays.
Two things this count deliberately does not do: it does not subtract public holidays, which vary by country and by company, and it does not prorate partial days. If you need a holiday-aware figure, take the weekday count from here and subtract the holidays that fall inside the range from your own calendar. For SLA and project-planning work that distinction matters, so it is worth stating explicitly rather than discovering it later.
You do not need two different dates. To measure the time between two times on the same day—a shift, a maintenance window, a meeting that overran—set the same date on both sides and enter the two clock times. A shift from 22:15 to 06:45 that crosses midnight is handled by advancing the end date by one day; the calculator will then report 8h 30m. If you enter an end that precedes the start without adjusting the date, the tool flags it with an “end date is before start date” warning and shows the magnitude of the negative span rather than silently returning a wrong positive number.
Times are interpreted in your computer’s local timezone on both sides. That is the right behaviour for timesheets and local scheduling, but it means the calculator is not the right tool for spans that cross timezones. For that, and for finding meeting windows across regions, use the world clock and timezone meeting planner.
00:00 if you leave it blank, so a pure days-between-two-dates calculation needs only the two date fields. A “now” shortcut fills both fields with the current moment.In Add or Subtract mode the layout changes slightly: you supply one starting date and time plus a quantity of days, hours, minutes, and seconds, and the tool returns the resulting date and time in both a human-readable form and an ISO date and time you can paste into code or a config file.
101d 8h, 2,432 hours, and 73 business days—the last figure being the one to compare against a sprint plan.5h 30m, or 19,800 seconds, which is what you would plug into a downtime credit calculation.Convert Units mode handles arbitrary combinations, but these are the values people look up most often.
| Duration | Hours | Minutes | Seconds |
|---|---|---|---|
| 15 minutes | 0.25 | 15 | 900 |
| 1 hour | 1 | 60 | 3,600 |
| 4 hours | 4 | 240 | 14,400 |
| 1 day | 24 | 1,440 | 86,400 |
| 2 days | 48 | 2,880 | 172,800 |
| 3 days | 72 | 4,320 | 259,200 |
| 1 week | 168 | 10,080 | 604,800 |
| 30 days | 720 | 43,200 | 2,592,000 |
Those eight values are also available as one-click presets under “Common Recovery Time Windows”. They are labelled for recovery time objectives and retention tiers because that is where round durations get quoted most, but the conversions are general purpose—the seconds column is what you want for a cache TTL, a token lifetime, or a cron interval.
Date objects in your local timezone, so a span crossing a DST boundary reflects the real elapsed time. A “24 hour” period across a spring-forward will correctly show 23 hours of elapsed time, not 24. That is physically accurate but occasionally surprising.If you are working with epoch values rather than calendar dates, the Unix timestamp converter translates between seconds-since-1970 and human dates, and the wider developer tools collection covers related date and scheduling utilities.
Choose Calculate Duration, enter the start date (and optionally a time), then the end date and time. The tool immediately shows the span as a compact d h m s value plus decimal totals in days, hours, minutes, and seconds, along with the number of business days in the range.
Enter the same date on both sides and set the two clock times. For a span that crosses midnight, set the end date to the following day so the calculation reflects the real elapsed time.
Yes. Every duration result includes a business-day count that excludes Saturdays and Sundays and includes both endpoint days. Public holidays are not deducted, since they differ by country and organisation.
The result panel reports total hours as a decimal alongside days, minutes, and seconds, so you never need to convert manually. For example, 13 days and 8.5 hours is shown as 320.50 hours.
Yes. Add Time and Subtract Time modes take a starting date and time plus a quantity of days, hours, minutes, and seconds, then return the resulting timestamp in both readable and ISO formats.
Yes. Durations are computed from real elapsed milliseconds in your local timezone, so a span crossing a DST change reports the true elapsed time rather than a naive calendar difference.
Yes. Your inputs are encoded into the page URL as you type, so copying the address bar and sending it reproduces exactly the same calculation on their screen.
No—both sides are interpreted in your device’s local timezone. For cross-timezone comparisons and meeting scheduling, use the world clock and timezone meeting planner instead.
No. Every calculation runs in your browser. Nothing you enter is transmitted or stored.
2,592,000 seconds, which is 720 hours or 43,200 minutes. Convert Units mode will produce that and any other combination you enter.
Enter a start date and end date (with optional times) and the calculator returns the exact duration in years, months, days, hours, minutes, and seconds. It also reports the total in each individual unit — useful when you need "how many days between two dates" rather than the broken-down form.
The tool handles add/subtract operations too: pick a starting moment, choose to add or subtract a quantity, and get the resulting date and time. Common operations like "what date is 90 days from today" or "what time will it be 8 hours and 45 minutes from now" are one click.
You committed to a 45-business-day delivery on a contract dated March 3. Enter March 3 as the start, toggle business days, and add 45 — the result is May 5. Now you know which week to start your QA buffer.
A friend turns 10,000 days old at some point. Enter their birthday as the start and today as the end; the totals row shows the exact day count. (Born January 1, 2000 → 10,000 days lands on May 19, 2027.)
Enter today as the start and the event date as the end. The result tells you both the calendar breakdown ("2 months, 14 days") and the raw count ("76 days"). Use the raw count for countdown widgets and the breakdown for human-readable copy.
Same workflow in reverse. Anniversaries, project kickoffs, last bug-free deploy — anything where you want to say "it has been N days since."
A 62-year-old planning to retire at 65 enters their date of birth as the start and a target retirement date as the end. The breakdown answers "how many years, months, and days from now," and the totals answer "how many paychecks" if you divide by your pay cycle.
Enter the effective date and the termination date. The totals row gives you total days for prorated billing; the breakdown gives you the "X years, Y months" language most contracts use.
Use add/subtract or duration between two times on the same day for a single shift; toggle working-hours mode for a multi-day timesheet that should ignore weekends and after-hours minutes.
Leap years. February 29 exists in 2000, 2004, 2008, ..., 2024, 2028. A duration of "one year" from Feb 29, 2024 lands on Feb 28, 2025 (non-leap) or Mar 1, 2025 depending on convention — this tool uses the Feb 28 convention, which matches how most legal documents and birthdays are handled. January 1 to December 31, 2025 = 364 days. January 1, 2024 to December 31, 2024 = 365 days (leap year, includes Feb 29).
Daylight saving transitions. In the US, clocks jump forward on the second Sunday of March (losing an hour) and fall back on the first Sunday of November (gaining an hour). A duration spanning March 9, 2025 at 1am to March 9, 2025 at 4am is 2 hours in wall-clock time but 3 hours of elapsed real time. This calculator reports elapsed real time — the unambiguous, physics-based answer.
Time-of-day matters. Jan 1 at 11:59pm to Jan 2 at 12:01am is 2 minutes, not 1 day. If you enter only dates with no times, both are treated as midnight and the result is exactly 1 day. Always include times when sub-day precision matters.
Time zone handling. The calculator runs in your local browser time zone. For cross-zone durations (e.g., a flight from JFK to LHR), convert both endpoints to UTC first, then enter them — or use the world clock tool to do the conversion side-by-side.
Inclusive vs. exclusive endpoints. A duration from Monday to Friday is 4 days (exclusive of the start) or 5 days (inclusive of both endpoints). This tool reports exclusive duration — the standard mathematical definition, and what you want for elapsed time. If you need inclusive counts (e.g., "I'm on vacation Mon through Fri, how many vacation days?"), add 1 to the result.
Duration is the elapsed time between two moments. It is not the number of calendar days touched, not the number of midnights crossed, and not the number of weekdays in the range. It is simply: end-time minus start-time, expressed in whatever units you find useful.
That distinction matters because most off-by-one errors in date math come from confusing duration with one of the other counts. "How many days are between Monday and Wednesday?" can legitimately mean 2 (duration), 3 (inclusive count of named days), or 1 (Tuesday is the only day strictly between them). This calculator always returns duration. If you need a different definition, do the small mental adjustment at the end — but start from an unambiguous number.
Enter the earlier date as the start and the later date as the end, then read the days figure in the totals strip. The calculator returns the exact number of days between the two dates — exclusive of the start day — with leap years and varying month lengths handled automatically, so no manual counting is needed.
Add a time to each date (the time field is optional) and the calculator returns the gap in hours, minutes, and seconds. For a single day, enter both times on the same date; for an overnight span, enter full start and end timestamps and it carries the math across midnight. For example, 9:15 AM to 5:45 PM is 8 hours 30 minutes.
Use the business-days option, which counts only Monday through Friday and skips Saturdays and Sundays. Calendar days and business days can differ by about 28% over a month, so business days is the right measure for SLAs, delivery windows, payroll, and project deadlines, while calendar days suit billing and contract terms.
Yes. Leap years (including the century-year exceptions) are handled automatically, so a one-year span lands on the correct date. Durations also reflect true elapsed time across daylight saving transitions, meaning a span over a clock change is reported in real hours rather than wall-clock hours.
The calculator runs in your browser local time zone. For a duration that crosses time zones — such as an international flight — convert both the start and end to the same zone (or to UTC) before entering them, so the result is not skewed by the offset between zones.
Switch to Add Time or Subtract Time, enter a starting date and time, and supply the quantity in days, hours, minutes, or seconds. The calculator returns the resulting date and time, answering questions like “what date is 90 days from today” or “what time will it be 8 hours from now.” Enter 14 days to add two weeks.
Read the total days from the totals strip and divide by 7. For example, 92 days between two dates is about 13.1 weeks. The calculator shows exact days; weeks are simply days divided by 7, and months vary in length so weeks give a steadier planning figure.