Hours Calculator

Calculate elapsed time between two clock times, including overnight shifts and optional breaks.

Your elapsed time will appear here.

About the Hours Calculator

Work shifts and appointment times are written in base-60 clock notation, while payroll and billing often need decimal hours. This calculator bridges those formats and can combine or subtract time intervals without treating minutes as hundredths of an hour.

The distinction between 1 hour 30 minutes and 1.30 decimal hours is important. Thirty minutes is half an hour, so 1:30 equals 1.5 hours, not 1.30 hours.

How to Use the Hours Calculator

  1. Enter each duration or start/end time in the format shown by the calculator.
  2. If the interval crosses midnight, use the option or date context that tells the calculator the end time is on the following day.
  3. Choose whether you need hours-and-minutes output or decimal hours for payroll, billing or analysis.
  4. Subtract unpaid breaks separately when the calculation is meant to represent paid or billable time.

How the Calculation Works

Clock durations are converted to a common minute total before addition or subtraction. Decimal hours are then calculated as total minutes ÷ 60.

For start/end times, each clock time can be represented as minutes from midnight. The end value is adjusted for an overnight interval when appropriate, and the difference is converted back to hours and minutes or decimal hours.

Worked example

Hours Calculator Worked Example

7 hours 45 minutes as decimal hours

Convert the 45 minutes to hours: 45 ÷ 60 = 0.75. Add that to 7 hours: 7 + 0.75 = 7.75 hours. Writing 7.45 would be incorrect because decimal hours use base 10, while minutes use base 60.

Result guide

Understanding Your Hours Calculator Result

Use hours-and-minutes output when communicating ordinary elapsed time. Decimal hours are better for multiplying by an hourly rate, but keep enough precision to avoid payroll or billing errors.

Before you rely on the answer

Assumptions and Limitations

  • Start and end times refer to the intended day or overnight interval.
  • Breaks are included or excluded consistently.
  • Daylight-saving changes and time zones require actual date/time-zone handling if they matter.

Practical tip

Using This Result in Practice

For payroll, keep the original clock times as a record and use decimal conversion only for the calculation. That makes rounding decisions easier to audit later.

Related calculations

Useful Calculations to Continue With

If you need to compare several clock times or a more explicit elapsed duration, use the Time Duration Calculator.

For employee shifts with breaks and repeated entries, the Time Card Calculator is designed around payroll-style time records.

Common questions

Hours Calculator FAQ

Why is 1 hour 30 minutes equal to 1.5 hours?

Thirty minutes is 30 ÷ 60 = 0.5 of an hour. Decimal hours are based on fractions of 60 minutes, not on writing minutes after a decimal point.

How do I calculate an overnight shift?

Treat the ending time as occurring on the following day. For example, 10:00 PM to 6:00 AM is an 8-hour interval before breaks.

Should I round decimal hours for payroll?

Use the employer’s or jurisdiction’s approved rounding policy. The calculator can provide the arithmetic, but it does not decide payroll-law rules.