About this calculator

An hours calculator converts between hours, minutes, and decimal hours and can sum time spans.

Who should use it: Workers, freelancers, and students logging time.

When to use it: Use it when timesheets mix hh:mm and decimal hour formats.

Hours and minutes arithmetic

Convert each time to minutes, add or subtract, then convert back. Duration between clock times measures forward and wraps past midnight when needed.

Step-by-step

1. 1

   Choose a mode

   Add, subtract, convert, or measure duration between clock times.

2. 2

   Enter times

   Provide hours and minutes, or a decimal hours value.

3. 3

   Calculate

   Review hours, leftover minutes, total minutes, and decimal hours.

Worked example: 2h 30m + 1h 45m

Convert 2 hours 45 minutes to decimal hours, then add 1.25 hours for a timesheet total.

1. 2h 30m = 150 minutes
2. 1h 45m = 105 minutes
3. Total = 255 minutes = 4h 15m

Result is 4h 15m (4.25 decimal hours).

How to interpret the result

Decimal 1.5 hours equals 1:30 — minutes are base-60, not base-100.

Key definitions

Decimal hours

Time expressed as a fractional hour, e.g. 1.5 = 1 hour 30 minutes.

Duration

Elapsed time between two clock times.

Midnight wrap

When end < start, duration continues into the next day.

Common use cases

• Timesheet prep
• Study session planning
• Travel and shift duration checks

Tips

• For payroll with overtime rules, continue in the Time Card Calculator.
• Use decimal mode when spreadsheets expect fractional hours.

Common mistakes

Limitations

• Does not apply payroll rounding rules unless you encode them.
• Overnight shifts may need date context from a timesheet tool.