Calculate the duration between two times, add multiple time spans, or subtract durations. Handles overnight shifts with auto midnight-crossing detection, converts results to decimal hours for payroll, and supports unlimited duration entries. Perfect for tracking work hours, exercise sessions, project tasks, and billing.
Calculate the duration between two times, add multiple time spans together, or subtract one duration from another. Perfect for tracking work hours, exercise sessions, and project time.
| Total hours (decimal) | 8.5 |
| Total minutes | 510 |
| Total seconds | 30600 |
A time duration calculator measures the length of an event — the elapsed time between a start and end, the sum of multiple sessions, or the difference between two durations. It operates in hours, minutes, and seconds, making it the go-to tool whenever you need precise time arithmetic.
Unlike a date calculator (which works with calendar days), a time duration calculator focuses on the clock: shifts, sessions, workouts, cooking timers, and anything else measured in HH:MM:SS. It handles overnight shifts automatically, converts results to decimal hours for payroll, and can chain multiple durations with ease.
Calculate shift duration, overtime hours, and breaks. Convert to decimal hours for payroll (8h 30m = 8.5 hours × hourly rate).
Log workout sessions, calculate rest intervals, sum up weekly training hours, and track time for each exercise set.
Add prep time + cook time + rest time to get total meal duration. Calculate when to start so dinner is ready at the right moment.
Sum billable hours across tasks, calculate sprint velocity in person-hours, or track time logged against a project budget.
Precisely calculate the duration of overnight shifts that cross midnight — the tool auto-detects or lets you toggle '+1 Day'.
Add video clip durations to find total runtime. Calculate reading time, podcast run length, or class session totals.
All time arithmetic reduces to a single unit — seconds — then converts back to H:M:S for display.
Duration = End (sec) − Start (sec)
If result < 0, add 86 400 s (crosses midnight)Both times are converted to seconds-since-midnight, then subtracted. If the result is negative, the end time is on the next day and 86 400 seconds (24 hours) is added automatically.
Total = Σ (hₙ × 3600 + mₙ × 60 + sₙ)Each duration entry is independently converted to seconds. All values are summed, then decomposed back into days, hours, minutes, and seconds. No 24-hour cap — the result may exceed 24 hours.
Result = Base (sec) − Subtract (sec)Useful for overtime (actual − standard = overtime) or remaining time (time-box − elapsed = remaining). A negative result means the subtract value exceeded the base.
Decimal hours = total seconds ÷ 3600
Minutes = total seconds ÷ 60The decimal-hours format is used in payroll, billing, and data entry. For example, 8 hours 45 minutes = 8.75 decimal hours. Total minutes are useful for distance/speed calculations.
Mode: Between Two Times
| Start time | 09:00:00 |
| End time | 17:30:00 |
| Seconds diff | 63 000 − 32 400 = 30 600 s |
| Duration | 8h 30m 0s (08:30:00) |
| Decimal hours | 8.5 hrs × $20/hr = $170.00 gross |
Mode: Add Durations
| Session | Duration |
|---|---|
| Morning coding | 2h 30m 0s = 9 000 s |
| Afternoon review | 1h 45m 0s = 6 300 s |
| Evening testing | 3h 15m 0s = 11 700 s |
| Total | 7h 30m 0s (07:30:00) = 7.5 hrs |
Mode: Subtract Duration
| Hours worked (base) | 10h 30m = 37 800 s |
| Standard day (subtract) | 8h 0m = 28 800 s |
| Overtime | 2h 30m = 2.5 hrs at 1.5× rate |
Mode: Between Two Times with +1 Day toggle
| Start time | 22:30:00 |
| End time | 06:00:00 + 86 400 s |
| Calculation | (21 600 + 86 400) − 81 000 = 27 000 s |
| Duration | 7h 30m 0s (07:30:00) |
Time Duration Calculator is part of the Time & Date collection. If you want a broader view of similar workflows, open the Time & Date category page or browse all QuickTools categories.
Common next steps after this tool include Date Difference Calculator, Time Zone Converter and Age Difference Calculator.
Calculate the exact number of days, weeks, months, and years between any two dates. Includes business days, weekend days, total hours, minutes, and seconds. Perfect for project planning, legal deadlines, event countdowns, age calculations, and contract periods.
Convert any date and time across 50+ world time zones instantly. Automatically handles UTC offsets, Daylight Saving Time (DST), and fractional offsets like UTC+5:30. Perfect for scheduling international meetings, coordinating remote teams, planning travel, and tracking global market hours.
Find the exact age gap between two people in years, months, and days. Calculates individual ages, zodiac signs, Chinese zodiac, birth generation, days until next birthday, combined ages, and the relative percentage by which one person is older. Perfect for couples, siblings, parent-child comparisons, and celebrity age gap curiosity.
Calculate your weekly work hours with automatic overtime detection, break deductions, and pay estimates. Enter start/end times and breaks for each day of the week, set your hourly rate and overtime multiplier, and get a full day-by-day breakdown with regular hours, overtime hours, and gross pay. Handles overnight shifts, compressed workweeks, and both daily and weekly overtime thresholds.
Format, validate, minify, or sort JSON data with configurable indentation. Instantly check for syntax errors, view node count and nesting depth — free, no sign-up required.
Generate QR codes for URLs, text, Wi-Fi credentials, vCards, and more. Customise foreground and background colour, error correction level, margin, and download as SVG or PNG — free and instant.
Calculate your Body Mass Index, healthy weight range and ideal weight using metric or imperial units.
Estimate daily calorie needs based on age, gender, height, weight and activity level using Mifflin-St Jeor, Harris-Benedict or Katch-McArdle formulas.