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Your Free Digital Swiss Army Knife

Time Duration Calculator

Time Duration Calculator
Add or Subtract hours and minutes to calculate total time.

Time Duration Calculator: Add & Subtract Hours

Struggling to calculate your weekly work hours? Need to subtract a lunch break from your daily shift? Standard calculators don’t work with time formats (base 60), which makes adding “8:45” and “3:20” a headache.

Our Time Duration Calculator is designed specifically for time math. You can create a list of multiple time entries, choose to add or subtract each one, and get the precise total in both “Hours:Minutes” and decimal format for payroll.

💡 FAQ Section

What are "Decimal Hours"?

It’s for payroll.

If you work 1 hour and 30 minutes, your boss calculates it as 1.5 hours.

Standard time (1:30) cannot be multiplied by an hourly wage rate.

Our tool converts your total time into decimals automatically (e.g., 8:15 = 8.25), saving you an extra conversion step.

How do I handle lunch breaks?

Use the Subtract (-) button.

If you clocked in at 9:00 and worked for 8 hours but took a 45-minute lunch break, enter “8:00” with a (+), then add a new row, toggle the button to (-), and enter “0:45”.

The calculator will subtract the break correctly.

Can I calculate negative time?

Yes. This is useful for “Time Off in Lieu” (TOIL) or managing a time bank.

If you owe your employer 2 hours but work 30 minutes overtime, the calculator will show you are still -1:30 in debt.

Negative totals appear in red for clarity.

Is there a limit to rows?

No. You can add as many rows as you need.

Whether you are summing up a whole week of freelance work (5-7 rows) or a month of overtime shifts, the list expands dynamically.

Scroll through your entries easily within the widget.

Why Choose This Tool?

1. Smart Input Logic:

We designed it for speed. When you type “08” in the hour field, the cursor automatically jumps to the minute field, so you can type “0845” continuously without clicking or pressing Tab. It makes data entry lightning fast.

2. Visual Clarity:

Stop squinting at spreadsheets. We use color coding (Blue for +, Red for -) to make your list readable at a glance. You can easily spot if you accidentally set a work shift to “subtract” instead of “add”.

3. Cross-Platform Privacy:

Your time logs are private. Whether you are tracking hours for a client project or checking your own timesheet, the data stays on your device. We do not store or see your work hours.

💡 Pro Tip: Freelancers! Use the “Decimal Hours” result to bill your clients. If the tool says you worked 10:15 (10h 15m), bill for 10.25 hours. Multiply 10.25 by your hourly rate to get the exact invoice amount.