Date & Time

Time Calculator — Free 2026

Add or subtract hours, minutes, and seconds. Also add a duration to a specific clock time — free, instant, no sign-up.

Duration Arithmetic

Duration Result

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Result (HH:MM:SS)
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Total Hours
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Total Minutes
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Total Seconds

Clock Time Arithmetic

Clock Time Result

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Resulting Time

How It Works

  1. Choose an operation
  2. Enter two time durations
  3. Read your results
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How to Add and Subtract Time

Working with time arithmetic is a common need in everyday life — calculating shift lengths, tracking project hours, planning cooking times, or figuring out arrival times. Unlike regular numbers, time operates on a base-60 system for minutes and seconds, which makes mental arithmetic tricky. This calculator handles the conversions automatically so you can focus on the numbers that matter.

Duration Arithmetic

The duration section lets you add or subtract two time periods. Enter hours, minutes, and seconds for each, and the calculator converts everything to total seconds, performs the operation, then converts back to HH:MM:SS format. It also shows the total in hours, minutes, and seconds separately for convenience. For example, adding 2 hours 45 minutes to 1 hour 30 minutes gives 4 hours 15 minutes. If you subtract a larger time from a smaller one, the result will show as negative. This is useful for calculating date differences or planning schedules alongside our business days calculator.

Clock Time Arithmetic

The clock time section is different — it takes a specific time of day (like 2:30 PM) and adds or subtracts a duration to find the resulting clock time. This is perfect for questions like "If I start cooking at 4:15 PM and the recipe takes 1 hour 45 minutes, what time will dinner be ready?" The calculator wraps around midnight automatically, so adding 8 hours to 10:00 PM correctly gives 6:00 AM the next day.

Frequently Asked Questions

How do I add hours and minutes together?
To add two time durations, add the hours, minutes, and seconds separately. If the seconds total 60 or more, carry over to minutes. If the minutes total 60 or more, carry over to hours. For example, 2h 45m + 1h 30m = 4h 15m (45 + 30 = 75 minutes = 1 hour 15 minutes, then 2 + 1 + 1 = 4 hours).
How do I subtract time?
To subtract time, convert both durations to total seconds, subtract, then convert back. If the result is negative, the second duration was larger than the first. For example, 3h 15m minus 1h 45m: convert to minutes (195 - 105 = 90 minutes = 1h 30m).
Can I add time to a specific clock time?
Yes, this calculator supports adding or subtracting a duration from a specific clock time. For example, if it is 2:30 PM and you want to know what time it will be in 3 hours and 45 minutes, the result is 6:15 PM. The calculator handles midnight crossovers automatically.
How do I convert hours to minutes or seconds?
Multiply hours by 60 to get minutes, or by 3600 to get seconds. For example, 2.5 hours = 150 minutes = 9,000 seconds. To convert minutes to hours, divide by 60. This calculator shows results in all three formats automatically.

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