How to Calculate Work Hours — The Complete Guide for Employees & Employers
To calculate work hours, subtract your start time from your end time, deduct any unpaid breaks, and convert the remaining minutes to decimals by dividing by 60. Then sum each day's decimal total for the week. Any weekly total above 40 hours triggers overtime at 1.5× pay under federal law (FLSA). For example, a shift from 8:00 AM to 5:00 PM with a 30-minute lunch equals 8.50 decimal hours.
This guide walks through every step in detail — from reading a time card to handling overnight shifts and state-specific overtime rules — with verified math examples and references to federal labor regulations.
Work hours (also called hours worked) are the total compensable time an employee spends performing job duties or remaining under an employer's control. Under the Fair Labor Standards Act (FLSA), this includes all time an employer "suffers or permits" an employee to work, as defined in 29 CFR § 785.
To calculate work hours: record start/end times, subtract unpaid breaks, convert minutes to decimals (minutes ÷ 60), then sum the week. Any total above 40 hours typically triggers overtime at 1.5× the regular rate.
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Open Work Hours Calculator- What Does "Work Hours" Mean Legally?
- How Do You Calculate Work Hours From a Time Card?
- How Do You Convert Minutes to Decimal Hours for Payroll?
- What Are the FLSA Rules for Time Rounding?
- How Do You Handle Overtime in Work Hours Calculations?
- What Tools Can You Use to Calculate Work Hours?
- What Are Common Work Hours Calculation Mistakes?
- Frequently Asked Questions
What Does "Work Hours" Mean Legally?
Legally, "work hours" (or "hours worked") means all time an employer suffers or permits an employee to work — including active job duties, short rest breaks of 5–20 minutes, required training sessions, restricted on-call time, and travel between job sites during the workday. This definition comes from 29 CFR § 785 under the Fair Labor Standards Act.
The FLSA does not limit the number of hours an employee may work in a week, but it does mandate that all compensable time be tracked and paid. Understanding the boundary between compensable and non-compensable time is essential for accurate payroll.
Compensable vs. Non-Compensable Time
Not every minute between arrival and departure counts as paid time. The key distinction is whether the employee is "suffered or permitted" to work — meaning the employer knows or has reason to know the employee is performing duties.
Generally compensable: Active job duties, short rest breaks of 5–20 minutes (per 29 CFR § 785.18), required training sessions, waiting time when the employee cannot use the time for their own purposes, and on-call time when the employee's movements are significantly restricted.
Generally non-compensable: Meal periods of 30 minutes or longer when the employee is completely relieved of duties (per 29 CFR § 785.19), normal commuting from home to work, and time spent on voluntary training outside regular hours that is not directly related to the employee's job.
On-Call, Travel, and Training Time
Travel time rules vary by situation. Normal home-to-work commuting is not compensable, but travel between job sites during the workday, out-of-town travel during normal work hours, and travel to a different city for a one-day assignment are generally compensable under 29 CFR §§ 785.35–785.41. On-call time is compensable when the employee's freedom is restricted to the point that they cannot effectively use the time for their own purposes. Training is compensable unless it is voluntary, outside regular hours, not directly job-related, and no productive work is performed during it.
When in doubt, the FLSA errs on the side of the employee. If you are unsure whether time is compensable, consult the DOL Fact Sheet #22 on Hours Worked or seek legal counsel.
How Do You Calculate Work Hours From a Time Card?
To calculate work hours from a time card, follow five steps: record your start and end times, subtract start from end to get gross hours, deduct unpaid breaks, convert the remaining minutes to decimal format (minutes ÷ 60), and sum each day's total for the week. Any weekly total above 40 hours triggers overtime under federal law.
Whether you use a physical punch clock, a digital time-tracking app, or a paper timesheet, the calculation is the same. We will work through each step, then apply all five to a complete weekly example.
Step 1 — Record Start and End Times
Write down (or confirm) the exact clock-in and clock-out times for each work period. Use a consistent format — either 12-hour (AM/PM) or 24-hour notation. Using 24-hour time eliminates AM/PM errors and simplifies the arithmetic.
Tip: If a shift crosses midnight, convert the end time by adding 24 hours. For example, a shift ending at 2:00 AM becomes 26:00 in 24-hour math, making subtraction straightforward.
Step 2 — Calculate Gross Hours
Subtract the start time from the end time. Handle hours and minutes separately. If the minutes result is negative, borrow 1 hour (60 minutes) from the hours column — this is standard base-60 arithmetic.
Example: Clock in at 8:15 AM (08:15), clock out at 5:00 PM (17:00). Hours: 17 − 8 = 9. Minutes: 00 − 15 = −15, so borrow 1 hour: 8 hours and 45 minutes gross.
Step 3 — Subtract Unpaid Breaks
Deduct any unpaid meal periods from the gross total. Short rest breaks (5–20 minutes) are compensable under federal law and should not be subtracted.
Continuing the example: 8h 45m gross − 30m lunch = 8h 15m net.
Step 4 — Convert to Decimal Hours for Payroll
Most payroll systems require time in decimal format. Divide the remaining minutes by 60 to get the decimal equivalent, then add it to the whole hours.
For our example: 8 + (15 ÷ 60) = 8 + 0.25 = 8.25 decimal hours.
Step 5 — Sum the Week and Identify Overtime
Add all five (or six/seven) daily decimal totals. Under federal law, any total exceeding 40.00 hours in a single workweek is overtime, paid at a minimum of 1.5× the employee's regular rate of pay (29 CFR § 778).
| Day | Clock In | Clock Out | Break | Net (h:m) | Decimal |
|---|---|---|---|---|---|
| Monday | 8:00 AM | 5:15 PM | 30 min | 8h 45m | 8.75 |
| Tuesday | 7:45 AM | 5:00 PM | 30 min | 8h 45m | 8.75 |
| Wednesday | 8:00 AM | 5:30 PM | 30 min | 9h 00m | 9.00 |
| Thursday | 8:15 AM | 5:00 PM | 30 min | 8h 15m | 8.25 |
| Friday | 8:00 AM | 4:45 PM | 30 min | 8h 15m | 8.25 |
| Weekly Total | 43h 00m | 43.00 | |||
Result: 40.00 regular hours + 3.00 overtime hours. At $20/hour, the gross pay would be (40 × $20) + (3 × $30) = $800 + $90 = $890.00.
Verification — Monday's calculation: 5:15 PM = 17:15. Gross = 17:15 − 8:00 = 9h 15m. Minus 30m break = 8h 45m. Decimal: 8 + (45 ÷ 60) = 8.75. ✓
How Do You Convert Minutes to Decimal Hours for Payroll?
To convert minutes to decimal hours, divide the minutes by 60 and add the result to the whole hours. For example, 45 minutes ÷ 60 = 0.75 decimal hours. The three most common conversions are 15 min = 0.25, 30 min = 0.50, and 45 min = 0.75. Add the decimal result to the whole hours for the payroll-ready total.
Payroll software, spreadsheets, and accounting systems use decimal hours — not hours and minutes — because decimals multiply directly against hourly rates. The table below covers every 5-minute increment for quick reference.
Minutes-to-Decimal Conversion Table
| Minutes | Decimal | Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|---|---|
| 5 | 0.08 | 25 | 0.42 | 45 | 0.75 |
| 10 | 0.17 | 30 | 0.50 | 50 | 0.83 |
| 15 | 0.25 | 35 | 0.58 | 55 | 0.92 |
| 20 | 0.33 | 40 | 0.67 | 60 | 1.00 |
Common payroll decimals to memorize: 15 min = 0.25 (quarter hour), 30 min = 0.50 (half hour), 45 min = 0.75 (three-quarter hour). These three cover the majority of time-card rounding scenarios.
When converting manually, always keep at least two decimal places. Some payroll systems use four decimal places for precision — check your software's documentation. If you prefer to skip the math, our Work Hours Calculator converts automatically.
What Are the FLSA Rules for Time Rounding?
Under 29 CFR § 785.48(b), the FLSA permits (but does not require) employers to round employee clock times to the nearest 5, 6, or 15 minutes. The rounding practice must average out over time so employees are fully compensated — one-sided rounding that consistently favors the employer violates federal law.
The 7-Minute Rule Explained
The "7-minute rule" applies specifically to quarter-hour (15-minute) rounding. When an employer rounds to the nearest 15-minute mark, the midpoint of that interval is 7 minutes and 30 seconds. In practice, this means if an employee clocks in 1 to 7 minutes before or after a quarter-hour mark, the time rounds toward the nearest quarter-hour (which usually rounds down for early clock-ins). At 8 to 14 minutes, the time rounds up to the next quarter-hour.
| Actual Clock-In | Rounded To | Explanation |
|---|---|---|
| 8:05 AM | 8:00 AM | 5 min past the hour — rounds down (≤ 7) |
| 8:07 AM | 8:00 AM | 7 min past the hour — rounds down (≤ 7) |
| 8:08 AM | 8:15 AM | 8 min past the hour — rounds up (≥ 8) |
| 8:12 AM | 8:15 AM | 12 min past the hour — rounds up (≥ 8) |
Critical requirement: Rounding must average out fairly over time. An employer cannot adopt a rounding policy that systematically underpays employees — for example, always rounding clock-in times up and clock-out times down. If a rounding policy consistently favors the employer, it may violate the FLSA.
Compliant vs. Non-Compliant Rounding
Compliant: An employer rounds all punches to the nearest 15 minutes using the 7-minute rule consistently for both clock-ins and clock-outs. Over a pay period, some rounds favor the employee, some favor the employer, and the net difference is negligible.
Non-compliant: An employer rounds clock-in times up to the next quarter-hour but records exact clock-out times. This systematically reduces compensable minutes and would likely violate 29 CFR § 785.48(b).
How Do You Handle Overtime in Work Hours Calculations?
Under the FLSA, non-exempt employees must receive overtime pay of at least 1.5× their regular rate for all hours worked over 40 in a single workweek. Calculate overtime by summing your weekly decimal hours, subtracting 40, and multiplying the remainder by your regular rate × 1.5. Some states also require daily overtime after 8 or 12 hours.
Federal Overtime Rules
The federal overtime threshold is straightforward: anything beyond 40 hours in the defined workweek triggers overtime. There is no daily overtime requirement under federal law — an employee could work 12 hours on Monday and 28 hours the rest of the week (40 total) with zero overtime owed federally.
State Overtime Variations
Several states impose overtime rules that go beyond the federal standard. Here are some of the most notable examples:
| State | Daily OT Trigger | Weekly OT Trigger | Double-Time Trigger |
|---|---|---|---|
| California | > 8 hrs/day | > 40 hrs/week | > 12 hrs/day or 7th consecutive day > 8 hrs |
| Alaska | > 8 hrs/day | > 40 hrs/week | None |
| Colorado | > 12 hrs/day | > 40 hrs/week | None |
| Nevada | > 8 hrs/day (if rate < 1.5× min wage) | > 40 hrs/week | None |
| Federal (FLSA) | None | > 40 hrs/week | None |
Calculating the Regular Rate
The "regular rate" is not always the same as the hourly rate. Under 29 CFR § 778, the regular rate must include most forms of compensation: base wages, non-discretionary bonuses, shift differentials, and commissions. It excludes discretionary bonuses, gifts, vacation pay, and employer contributions to benefit plans.
An employee earns $18/hour and receives a $90 weekly production bonus. They work 45 hours this week.
Total straight-time compensation: (45 × $18) + $90 = $810 + $90 = $900
Regular rate: $900 ÷ 45 hours = $20.00/hour
Overtime premium: 5 overtime hours × ($20.00 × 0.5) = 5 × $10.00 = $50.00
Total pay: $900 + $50 = $950.00
For a faster way to calculate overtime, use our Overtime Calculator, which handles the regular rate computation automatically.
What Tools Can You Use to Calculate Work Hours?
The four main tools for calculating work hours are manual pen-and-paper, free online calculators, spreadsheets (Excel or Google Sheets), and dedicated time-tracking software. For individuals and spot-checks, a free online calculator is fastest. For teams of 5+ employees, a spreadsheet or time-tracking app provides better accuracy and audit trails.
The best method depends on your team size, budget, and compliance needs. Here is how the four approaches compare:
| Method | Best For | Pros | Cons |
|---|---|---|---|
| Manual (pen & paper) | Solo freelancers | Zero cost, no tech needed | Error-prone, slow, no audit trail |
| Online calculator | Small teams, spot-checks | Free, instant, handles decimals/overtime | No data storage, manual entry each time |
| Spreadsheet | Small businesses (1–20 employees) | Customizable, free templates, data saved | Formula errors possible, manual upkeep |
| Time-tracking software | Growing teams, compliance-heavy industries | Automated, GPS/geofencing, payroll integration | Monthly cost, learning curve |
For a deeper look at software options including pricing, features, and integration capabilities, see our Time Tracking Software Comparison.
Our recommendation: Start with a free online calculator like the Work Hours Calculator to verify your process, then graduate to a spreadsheet or dedicated software as your team grows. Whatever method you use, keep records for at least three years — the FLSA requires employers to maintain accurate time records under 29 CFR Part 516.
What Are Common Work Hours Calculation Mistakes?
The most common work hours mistakes are treating minutes as base-10 numbers instead of base-60, forgetting to deduct unpaid breaks, using one-sided time rounding, ignoring state daily overtime rules, and omitting non-discretionary bonuses from the overtime regular rate. Each error can cost hundreds to thousands of dollars per employee per year.
Payroll errors cost businesses time and money — and can trigger DOL investigations. Here are seven frequent mistakes with their dollar impact.
Time uses base-60, not base-10. Adding 2:45 + 1:30 as "2.45 + 1.30 = 3.75" gives 3 hours 75 minutes — which is wrong. The correct answer is 4 hours 15 minutes (45 + 30 = 75 minutes = 1 hour 15 minutes carry-over). Learn more about base-60 arithmetic.
Subtracting a 30-minute lunch seems simple, but it is frequently forgotten in manual calculations — especially when employees take breaks at inconsistent times. Always verify that break deductions appear on every pay period.
Rounding clock-in times up but recording exact clock-out times systematically favors the employer. Under 29 CFR § 785.48(b), rounding must average out fairly. One-sided rounding can result in back-pay claims and DOL enforcement action.
Federal law only requires weekly overtime, but states like California mandate overtime after 8 hours in a single day. An employee working four 10-hour days (40 weekly hours) would owe no federal overtime, but in California they would earn 8 hours of daily overtime that week.
Production bonuses, attendance bonuses, and shift differentials must be factored into the regular rate before calculating the overtime premium. Omitting them underestimates overtime pay and violates 29 CFR § 778.
A shift from 10:00 PM to 6:30 AM crosses midnight. Subtracting 10:00 PM from 6:30 AM directly yields a negative number. The fix: convert to 24-hour time and add 24 to the end time (22:00 to 30:30), then subtract normally: 30:30 − 22:00 = 8 hours 30 minutes.
Truncating 8.6667 hours to 8.66 instead of rounding to 8.67 seems trivial, but across hundreds of pay periods it compounds. Always round to at least two decimal places, and round the final digit correctly (5 rounds up).
Frequently Asked Questions
Record your clock-in and clock-out times each day, subtract any unpaid breaks (typically 30 minutes for lunch), then convert each day's hours and minutes to decimal form by dividing minutes by 60. Sum all daily totals. Any total above 40.00 hours in a single workweek is typically overtime at 1.5× your regular rate under the FLSA.
Divide the minutes by 60. For example, 45 minutes ÷ 60 = 0.75 decimal hours. The three most common conversions worth memorizing are 15 min = 0.25, 30 min = 0.50, and 45 min = 0.75. For other values, use our conversion table or the Work Hours Calculator.
Under federal law (FLSA), meal periods of 30 minutes or more are not compensable if the employee is completely relieved of duties. However, short rest breaks of 5–20 minutes are generally considered compensable work time under 29 CFR § 785.18. Some states have additional meal break requirements — for example, California requires a 30-minute meal period before the end of the fifth hour of work.
The 7-minute rule applies specifically to quarter-hour (15-minute) rounding under 29 CFR § 785.48(b). If an employee clocks in 1–7 minutes past a quarter-hour mark, the time rounds down to that mark. At 8–14 minutes past, the time rounds up to the next quarter-hour. This practice must average out fairly over time so employees are fully compensated for all hours actually worked.
Under federal FLSA rules, overtime is paid at 1.5× the employee's regular rate for all hours worked over 40 in a workweek. Multiply the overtime hours by the regular hourly rate, then multiply that by 1.5. Remember to include non-discretionary bonuses and shift differentials in the regular rate calculation. Use our Overtime Calculator for automatic results.
It depends on the type of travel. Normal home-to-work commuting is not compensable. However, travel between job sites during the workday, one-day out-of-town assignments, and travel during normal work hours on overnight trips are generally considered compensable under 29 CFR §§ 785.35–785.41. Check the DOL Fact Sheet #22 for specific guidance.
Gross hours are the total elapsed time from clock-in to clock-out, including all breaks. Net hours (also called compensable hours) are what remains after subtracting unpaid meal periods. Payroll should always be calculated on net hours. For example, clocking in at 8:00 AM and out at 5:00 PM gives 9 gross hours; minus a 30-minute unpaid lunch = 8.5 net hours.
Yes. Under 29 CFR § 785.48(b), the FLSA permits employers to round employee clock times to the nearest 5, 6, or 15 minutes. The key requirement is that rounding must average out so employees are fully compensated over time. A rounding policy that consistently favors the employer may violate federal law.
Convert both times to 24-hour format, then add 24 to the end time if it falls after midnight. For example, a shift from 10:00 PM to 6:00 AM becomes 22:00 to 30:00. Subtract normally: 30:00 − 22:00 = 8 hours. Our Time Addition Calculator handles cross-midnight calculations automatically.
Yes. TimeAdditionCalculator.com offers several free calculators: the Work Hours Calculator computes daily hours from clock-in/clock-out times with automatic break deductions, the Timesheet Calculator handles full weekly timesheets, and the Overtime Calculator computes overtime pay. All run in your browser with no account or software installation required.
A standard full-time work year contains 2,080 hours, based on 40 hours per week × 52 weeks. After accounting for typical paid time off (federal holidays and vacation), actual working hours range from roughly 1,800 to 1,950 per year depending on the employer's leave policy. To calculate your personal total, multiply your average weekly hours by 52 and subtract any unpaid leave.
The formula is: (Clock-Out Time − Clock-In Time) − Unpaid Breaks = Net Work Hours. To convert to decimal for payroll, use: Hours + (Minutes ÷ 60). For example, 8 hours 45 minutes minus a 30-minute break equals 8 hours 15 minutes, which converts to 8 + (15 ÷ 60) = 8.25 decimal hours.
Enter clock-in and clock-out times in separate cells formatted as Time (h:mm AM/PM). In a third cell, use the formula =(B2−A2)×24 to get decimal hours, where B2 is clock-out and A2 is clock-in. Subtract breaks with =(B2−A2−C2)×24, where C2 contains the break duration. Format the result cell as Number with two decimal places for payroll use.
Track in whichever format your time clock uses (usually hours and minutes), but always convert to decimals before submitting to payroll. Decimal hours multiply directly against hourly rates without extra conversion, which reduces errors. Most payroll software, including ADP, Gusto, and QuickBooks, requires decimal input. Use the formula minutes ÷ 60 for the conversion.
Other Free Time Calculators
More tools to simplify your time tracking and payroll workflow.
Time Addition Calculator
Add multiple time values in hours, minutes, and seconds with instant decimal conversion.
Work Hours Calculator
Calculate daily work hours from clock-in/clock-out times with break deductions.
Timesheet Calculator
Full weekly timesheet with automatic totals, overtime detection, and pay estimates.
Time Subtraction Calculator
Subtract time values to find durations, elapsed time, and remaining time.
Elapsed Time Calculator
Find the exact duration between two dates and times, down to the second.
Overtime Calculator
Calculate overtime pay with federal and state rules, including regular rate adjustments.
Disclaimer: This guide is provided for educational purposes only and does not constitute legal or financial advice. Federal and state labor laws are subject to change; always verify current regulations with the U.S. Department of Labor Wage and Hour Division or a qualified employment attorney. Calculations should be reviewed by a payroll professional before use in actual compensation decisions.
Last updated: February 7, 2026