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Time Calculations4 min read

How to Calculate Time Duration and Decimal Hours

A guide to calculating elapsed hours and minutes, handling overnight shift rollovers, and converting time to decimal format for payroll.

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The Basic Calculation

Subtract start minutes from end minutes. If minutes are negative, subtract 1 from hours and add 60 to minutes.

Overnight Shift Calculations

When an employee starts work at 10:00 PM (22:00) and clocks out at 6:30 AM the following morning, adding 24 hours (1,440 minutes) to the end time provides the correct 8 hours and 30 minutes duration.

Converting to Decimal Hours for Payroll

To convert minutes to decimal hours for billing or payroll spreadsheets, divide the minutes by 60. For example: 8 hours 15 minutes = 8 + (15 / 60) = 8.25 hours.

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