Practical tools for measured work
Duration calculator
Normalize hours, minutes and seconds and subtract another duration.
Calculate the layout, check the diagram, then print the result for the shop or jobsite.
How it works
Add the first hours, minutes and seconds, then subtract the second set. Values above 59 are carried into the next unit. For example, 2 hours 90 minutes minus 1 hour 15 minutes equals 2 hours 15 minutes.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Hours
- 2
- Minutes
- 90
- Seconds
- 0
- Hours to subtract
- 1
- Minutes to subtract
- 15
- Seconds to subtract
- 0
Primary result: Normalized duration: 2:15:00.
Before using the result
- Check the selected mode, units and input values before using the result.
- Read the assumptions and rounding rules; compare the worked example with your intended calculation.
- A numerical result does not supply missing context or change the stated limitations.
Limitations
Each input must be nonnegative and at most one billion. The result may be negative. This is duration arithmetic with 60 seconds per minute and 60 minutes per hour, without calendar dates, time zones or leap seconds.
Frequently asked questions
How do I add two durations?
Add their hours in the Hours field, their minutes in Minutes and their seconds in Seconds. Set all subtraction fields to zero. The result normalizes the total.
How long will this task take?
Use the same quantity unit for the amount and rate.
How it works
Choose the kind of quantity, then enter your own measured or assumed rate. Time = quantity / rate. Add fixed setup and breaks, plus the entered percentage allowance on work time. The task selector labels your scenario; it does not invent a typical reading, writing, production or travel speed.
For 100 items at 20 items per hour, work takes 5 hours. A 20% allowance adds 1 hour; 10 minutes of setup gives 370 minutes in total. Change the inputs to compare realistic scenarios.
Current-input example
The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.
- Task quantity
- Items or repeated tasks
- Total quantity
- 100
- Your measured or assumed rate
- 20
- Rate period
- Quantity per hour
- Setup and fixed breaks
- 10 min
- Extra time allowance
- 20 %
Primary result: Estimated total minutes: 370 min.
Before using the result
- Check the selected mode, units and input values before using the result.
- Read the assumptions and rounding rules; compare the worked example with your intended calculation.
- A numerical result does not supply missing context or change the stated limitations.
Limitations
Assumes a constant rate. The allowance is a planning assumption, not a confidence interval. It does not account automatically for traffic, fatigue, parallel workers, queues or learning. Zero quantity still includes any entered setup time.
Frequently asked questions
What should I verify before using this result?
Check the input values, units, dates and assumptions. Compare the method and its stated limits with the source relevant to your task.
Why might the finished result differ?
Results depend on the entered data and the model’s assumptions. Rounding, changing conditions or omitted factors can affect the comparison. Read the limitations before using the result.
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Time unit converter
Convert seconds, minutes, hours and explicitly defined average months and years.