Calculation library

Work time guides

Clear, calculation-first explanations for common work-time questions.

Use a guide when the rule matters as much as the result

Calculators are fastest when you already know what you want to compute. Guides are better when you need to understand the steps, check a manual calculation, or see why two similar-looking time formats behave differently.

Most guides begin with the practical answer, then show formulas, worked examples, edge cases, and links to the matching calculator or reference page. Longer guides include an on-page table of contents so you can jump directly to the part you need.

Topic

Work Hours & Time Cards

Calculate shifts, breaks, weekly totals, time cards, and clock-out times.

How to Calculate Hours WorkedSubtract start time from end time, then subtract unpaid breaks.How to Calculate Work Hours With LunchLunch is unpaid only when it does not count toward work time.How to Calculate Overnight Shift HoursTreat an end time earlier than the start as occurring the next day.How to Calculate Weekly Work HoursAdd each completed day’s worked duration.How to Total a Time CardCalculate every row after breaks, then add the daily totals.Time Card Hours and MinutesKeep totals in hours and minutes until you need decimal hours.How to Calculate Clock-Out TimeAdd required paid work time and unpaid breaks to clock-in time.

Topic

Decimal Time

Understand base-10 hour notation and convert cleanly between minutes, hours-and-minutes, and decimal hours.

What Are Decimal HoursDecimal hours express minutes as a fraction of 60.How to Convert Minutes to Decimal HoursDivide minutes by 60.How to Convert Decimal Hours to Hours and MinutesMultiply the decimal by 60 to find minutes.Decimal Hours for PayrollDecimal-time payroll arithmetic converts minutes into fractions of an hour.Decimal Hours vs Hours and MinutesClock time uses base 60; decimal time uses base 10 fractions.Quarter Hour Decimal TimeQuarter-hour increments convert cleanly to decimals.

Topic

Time Duration

Work with elapsed time, midnight rollover, and adding or subtracting durations from clock times.

How to Calculate Time DurationFind the difference between a start and end time.How to Calculate Time Across MidnightWhen end time is earlier, place it on the following day.How to Add Hours and Minutes to a TimeAdd the duration to the clock time and wrap after midnight.How to Subtract Hours and Minutes From a TimeSubtract the duration and wrap before midnight.Time Duration vs Decimal HoursDuration is hours/minutes; decimal hours are a converted numerical form.

Topic

Overtime Arithmetic

Understand threshold-based hour splits and pay arithmetic without treating the calculator as a legal determination.

How to Calculate Overtime HoursCompare total hours with an editable regular-hours threshold.How to Calculate Overtime PayMultiply overtime hours by rate and multiplier.Regular Hours vs Overtime HoursRegular hours are the portion at or below a chosen threshold.

Topic

Business & Working Days

Count Monday–Friday dates, work with manual exclusions, and distinguish weekday counts from calendar-day counts.

What Is a Business DayThis site counts Monday through Friday as business days.Business Days vs Calendar DaysCalendar days include every date; business days omit weekends here.How to Calculate Business Days Between DatesCount Monday–Friday dates between the selected dates.How to Add Business Days to a DateMove forward by weekdays; the start date is not counted.How to Subtract Business Days From a DateMove backward by weekdays; the start date is not counted.How to Count Working Days in a MonthCount every Monday–Friday in the chosen month.How to Count Working Days in a YearAdd weekday counts across all twelve months.Do Weekends Count as Business DaysUnder this site’s model, Saturdays and Sundays are not business days.Business Days and HolidaysHolidays are excluded only when you enter them as excluded dates.

Keep calculations and external rules separate

Hourformula's guides explain deterministic time and date arithmetic. Some real-world tasks—such as payroll treatment, overtime eligibility, holiday schedules, or contractual deadlines—depend on rules outside the arithmetic itself. When that context matters, use the guide to understand the calculation and verify the external rule separately.