Time CalculatorFree online other calculator — instant results, no sign-up
Add or subtract hours, minutes and seconds.
How the result changes with hours
Each row below was calculated with this tool, keeping every other input at its default and changing only hours from half to one and a half times the default value. Use it to see how sensitive the answer is before you enter your own numbers.
| Hours | Result | In minutes |
|---|---|---|
| 1 | 3h 15m | 195 |
| 1.5 | 3h 45m | 225 |
| 2 (default) | 4h 15m | 255 |
| 2.5 | 4h 45m | 285 |
| 3 | 5h 15m | 315 |
About the Time Calculator
This time calculator adds or subtracts two time intervals specified in hours and minutes. It provides the total duration as hours and minutes as well as a single minute value. It is commonly used for scheduling, tracking cumulative project tasks, and calculating shifts.
- Hours
- Number of hours in the first time duration (typically 0 or greater).
- Minutes
- Number of minutes in the first time duration (typically 0 to 59).
- Op
- Arithmetic operator: select '+' to sum the two durations or '−' to subtract the second duration from the first.
- Hours
- Number of hours in the second time duration (typically 0 or greater).
- Minutes
- Number of minutes in the second time duration (typically 0 to 59).
Formula and method
t = (h1 × 60 + m1) ± (h2 × 60 + m2) Result = floor(|t| / 60)h (|t| mod 60)m
- h1Hours of the first time span
- m1Minutes of the first time span
- h2Hours of the second time span
- m2Minutes of the second time span
- tNet total time expressed in minutes
Each hour-minute input pair is converted into total minutes by multiplying hours by 60 and adding minutes. The second value is added to or subtracted from the first according to the operator. The absolute value of the net minutes is then formatted into hours and minutes, while the signed total is reported in minutes.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Hours2
- Minutes45
- Op+
- Hours1
- Minutes30
Results
- Result4h 15m
- In minutes255
How to use the Time Calculator
- 1Multiply the first hour value by 60 and add the first minute value to get initial minutes.
- 2Multiply the second hour value by 60 and add the second minute value to get secondary minutes.
- 3Add or subtract the secondary minutes from the initial minutes based on the chosen operator.
- 4Format the absolute resulting minutes into whole hours and remaining minutes, and output the net total minutes.
Reading your result
The 'Result' field displays the final duration broken into hours and minutes (e.g., '4h 15m'). The 'In minutes' field displays the total duration purely in minutes, including a negative sign if the subtraction yielded a negative result.
Limitations
This calculator operates only on hours and minutes and does not include seconds or calendar dates. It performs pure duration arithmetic and does not calculate time elapsed across specific times of day, time zones, or daylight saving transitions.
Common questions
What happens if subtracting results in a negative value?+
The 'In minutes' output displays the signed negative integer, while the 'Result' output displays the absolute magnitude of the duration in hours and minutes.
Can I input minute values greater than 59?+
Yes. The calculator converts all hours to minutes and adds whatever minute value is entered, automatically carrying excess minutes over in the final formatted hour-minute result.
Does this tool calculate clock times like 9:00 AM to 5:00 PM?+
No. It adds and subtracts fixed quantities of elapsed time (durations), rather than determining elapsed intervals between two clock timestamps.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.