Time & Shift Calculator

Add and subtract custom time intervals, sum multiple durations, or log roster sheets client-side.

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Add or Subtract Custom Time Intervals

Calculated Output
Accumulated Duration 0h 00m 00s
Hours Equivalent 0.00 Hours
Minutes Equivalent 0 Minutes
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Time Computations and Standardization

Because time is non-decimal (based on sexagesimal or base-60 numbering systems), summing or subtracting time units requires modulo conversion. Standard hours-to-decimals arithmetic utilizes division by 60 for minutes, and 3600 for seconds.

Decimal Hours = Hours + ( Minutes / 60 ) + ( Seconds / 3600 )

For example, if you accumulate a shift roster summing up to exactly **8 hours and 45 minutes**, the decimal equivalent is:

8 + ( 45 / 60 ) = 8.75 Hours

Frequently Asked Questions

If the shift End Time is earlier than the Start Time, the roster engine assumes the shift crosses midnight. It adds 24 hours to the end time before performing subtraction, resulting in precise duration logs (e.g. 10:00 PM to 6:00 AM logs exactly 8 hours).

Standard accounting packages require decimal formats to compute aggregate wages (e.g. multiplying Hourly Rate by 8.75 hours, rather than multiplying by 8:45, which would fail mathematically).