Hours and Minutes Calculator
Add or subtract time durations in hours and minutes, convert a duration to days, decimal hours or total seconds, and find the resulting clock time after adding your duration to any start time. All calculations update instantly in your browser.
How to add or subtract hours and minutes
The standard method is to convert each duration to a single count of minutes (multiply hours by 60, then add the minutes), perform the addition or subtraction on those minute totals, and finally convert back. To convert back, divide the total minutes by 60 to get whole hours, and the remainder is the leftover minutes. For example, adding 1 h 45 min and 2 h 30 min: 1 x 60 + 45 = 105 min, 2 x 60 + 30 = 150 min, 105 + 150 = 255 min, 255 / 60 = 4 h with 15 min left over, giving 4 h 15 min. This calculator handles those steps automatically, including carry-over when minutes exceed 59.
Decimal hours and payroll
Most payroll and billing systems expect time as a decimal, not as hours and minutes. To convert, divide total minutes by 60. 90 minutes becomes 1.50 hours, 75 minutes becomes 1.25 hours. Multiplying decimal hours by an hourly rate gives an exact dollar amount. For example, 2 h 15 min worked at $20/h is 2.25 x $20 = $45.00. This calculator shows the decimal equivalent alongside every result.
Adding a duration to a clock time
Sometimes you need to know the resulting wall-clock time rather than just a duration total. For example, if a meeting starts at 09:30 and runs for 1 h 45 min, it ends at 11:15. When the total crosses midnight, the result wraps to the next day. Switch the mode to "Add duration to a start time" and enter the start time in 24-hour format. The result shows the end time and flags if it falls on the next or a subsequent day.
Converting between time units
Beyond hours and minutes, time is often expressed in seconds (video editing, programming, music) or as a fraction of a day. The conversion mode shows all units at once: total minutes, decimal hours, total seconds and days. For quick reference, 1 hour = 60 minutes = 3,600 seconds. One day = 24 hours = 1,440 minutes = 86,400 seconds. The reference table below lists the most common benchmark durations.
Common time duration conversions
| Duration | Total minutes | Decimal hours | Total seconds |
|---|---|---|---|
| 1 minute | 1 | 0.0167 h | 60 |
| 15 minutes | 15 | 0.25 h | 900 |
| 30 minutes | 30 | 0.50 h | 1800 |
| 45 minutes | 45 | 0.75 h | 2700 |
| 1 hour | 60 | 1.00 h | 3600 |
| 1 h 30 min | 90 | 1.50 h | 5400 |
| 2 hours | 120 | 2.00 h | 7200 |
| 4 hours | 240 | 4.00 h | 14400 |
| 8 hours | 480 | 8.00 h | 28800 |
| 12 hours | 720 | 12.00 h | 43200 |
| 1 day (24 h) | 1440 | 24.00 h | 86400 |
| 1.5 days (36 h) | 2160 | 36.00 h | 129600 |
Reference values for converting between hours, minutes, seconds and decimal hours.
Frequently asked questions
How do I add hours and minutes correctly?
Convert each duration to minutes (hours x 60 plus minutes), add the totals, then divide by 60 for the hours and take the remainder for the leftover minutes. For example, 2 h 40 min + 1 h 35 min = 160 min + 95 min = 255 min = 4 h 15 min. The calculator does this automatically.
What is decimal hours and how do I convert from hours and minutes?
Decimal hours expresses time as a single number where the fractional part represents a fraction of an hour. Divide total minutes by 60. 1 h 30 min = 90 min / 60 = 1.50 h. 45 min = 45 / 60 = 0.75 h. It is used in payroll, billing, and spreadsheet formulas where multiplying hours by a rate must give an exact total.
How do I subtract time when the minutes would go negative?
Borrow one hour from the hour column and add 60 to the minutes. For example, 3 h 10 min - 1 h 45 min: borrow 1 h so you have 2 h 70 min - 1 h 45 min = 1 h 25 min. The calculator handles this automatically, and also shows a negative result when the second duration is longer than the first.
How many minutes are in 1.5 hours?
1.5 hours x 60 = 90 minutes. In general, multiply decimal hours by 60 to get minutes. 0.25 h = 15 min, 0.5 h = 30 min, 0.75 h = 45 min, 1.25 h = 75 min.
What happens if I add time that goes past midnight?
Use the "Add duration to a start time" mode and enter your start time in 24-hour format. If the result would exceed 23:59, the calculator wraps the clock time into the next day and labels it "(next day)". For example, 23:00 + 2 h 30 min = 01:30 (next day).
How many seconds are in an hour?
1 hour = 60 minutes = 60 x 60 = 3,600 seconds. One day = 24 x 3,600 = 86,400 seconds. The convert mode shows total seconds for any duration you enter.