Work Hours Calculator
Advanced calculator with quick entry and custom settings
Last updated: July 2026
Enter your start and end times, adjust the settings to match how your employer actually tracks time, and get your regular hours, overtime, and total hours in seconds. This calculator is free, requires no signup, and includes more customizable settings than a typical time calculator — clock format, rounding rules, a custom overtime threshold, break handling, and your week's start day.
How to Use This Work Hours Calculator
- Enter Time In and Time Out for each day — type the digits without a colon if you like. Typing
915becomes 9:15, and137becomes 1:37. - Pick AM or PM using the toggle next to each entry (skip this if you've switched to 24-hour format — see below).
- Enter break minutes for any unpaid time — 30 for a half-hour lunch, 60 for a full hour, or leave it at zero.
- Adjust the settings above the entry table to match your actual pay period rules (details on each one below).
- Read your totals — Regular Hours, Overtime Hours, and Total Hours all update instantly, shown in both hh:mm and decimal format.
Understanding the Settings
Most work hours calculators give you one or two options. This one gives you five, because real workplaces rarely follow identical rules. Here's what each setting actually does.
Clock Format (12-Hour vs. 24-Hour)
Some workplaces track time with AM/PM, others use 24-hour "military time" — a format where the clock runs from 00:00 to 23:59 instead of resetting at noon and midnight. If your timesheet, scheduling software, or employer uses military time, switch this setting to 24-hour and enter times like 1400 for 2:00 PM instead of toggling AM/PM. Switching back to 12-hour mode brings the AM/PM toggle back for each entry.
Rounding Rules (5, 6, or 15 Minutes)
Under U.S. federal timekeeping rules, employers are allowed to round clock-in and clock-out times to the nearest set interval, as long as the rounding is applied consistently and doesn't systematically shortchange employees. This calculator supports three rounding options:
- 15 minutes — also known as the 7-minute rule. A punch at 9:07 or earlier rounds down to 9:00; a punch at 9:08 or later rounds up to 9:15.
- 5 minutes — a punch at 9:02 rounds down to 9:00; 9:03 rounds up to 9:05.
- 6 minutes, also called 1/10-hour rounding — because 6 minutes is exactly one-tenth of an hour, every rounded time lines up cleanly with a decimal value (9:03 rounds down to 9:00; 9:04 rounds up to 9:06).
If your employer doesn't round at all, leave this setting off and every entry is used exactly as typed.
Custom Overtime Threshold
Under the Fair Labor Standards Act, overtime is generally owed after 40 hours in a single workweek — that's the default here. But not every situation matches that default exactly: some company policies, union agreements, or state rules set a different threshold. This calculator lets you change the 40-hour default to whatever number applies to you, or turn overtime off entirely to see a single combined total with no split.
Deduct Breaks Toggle
If the times you enter already exclude your lunch or break period, turn this off so nothing gets subtracted twice. If your Time In and Time Out represent the full span of your shift, breaks included, turn this on and enter your break minutes so they're deducted automatically.
Week Start Day
This one affects the math, not just the display. Overtime is calculated per workweek, and a workweek is a fixed, recurring 7-day period — it doesn't have to start on Monday. If your employer's official workweek starts on Sunday, but you calculate assuming a Monday start, hours can land in the wrong week and throw off your overtime total. Set this to match whatever day your employer's workweek actually begins.
How to Calculate Work Hours Manually (Step by Step)
The calculator does this instantly, but it helps to know the math — both to double-check results and to understand what's happening under the hood.
Step 1: Subtract start time from end time. 8:00 AM to 5:00 PM = 9 hours.
Step 2: Deduct any unpaid break. 9 hours − 30 minutes = 8 hours 30 minutes.
Step 3: Convert the minutes to decimal. Divide by 60. 30 minutes ÷ 60 = 0.50, so 8 hours 30 minutes = 8.50 hours.
Step 4: Repeat for each day and add up the week. Five days at 8.50 hours = 42.50 total hours.
Step 5: Apply the overtime threshold. At the standard 40-hour threshold: 40.00 regular hours, 2.50 overtime hours.
That's straightforward for a handful of identical days — it gets tedious fast once shifts vary, breaks differ, or rounding is involved. That's exactly what the calculator above handles automatically.
Converting Hours and Minutes to Decimal Time
Payroll and billing systems run on decimal hours, not clock time, since decimal numbers can be multiplied directly by an hourly rate. The conversion is always the same: divide the minutes by 60.
- 15 minutes ÷ 60 = 0.25
- 30 minutes ÷ 60 = 0.50
- 45 minutes ÷ 60 = 0.75
For minutes that don't divide evenly — say, 22 minutes — the same formula still applies: 22 ÷ 60 = 0.3667, which rounds to 0.37. Going the other direction, multiply a decimal by 60 to get minutes back: 0.4 × 60 = 24 minutes.
Frequently Asked Questions
What is military time format?
Military time (also called 24-hour format) numbers the hours 00 through 23 instead of resetting at noon and midnight, so there's no need for AM or PM. 2:00 PM becomes 14:00, and midnight is 00:00. It's the default time format in most of the world outside the US, and common in scheduling, logistics, and payroll systems.
How do I convert 24-hour time to 12-hour time?
If the hour is 13 or higher, subtract 12 and add PM — 14:00 becomes 2:00 PM. If the hour is 12, it stays 12 PM (noon). If the hour is 00, it becomes 12 AM (midnight). Anything from 1 to 11 stays the same and gets AM. This calculator handles the conversion automatically when you switch the Clock Format setting.
How does the 7-minute rounding rule work?
It rounds clock times to the nearest 15-minute mark. A punch within the first 7 minutes past the quarter-hour rounds down; a punch at 8 minutes past or later rounds up to the next quarter-hour. For example, 9:07 becomes 9:00, while 9:08 becomes 9:15.
How is overtime calculated if I change the threshold?
The calculator adds up your total hours for the period, then splits them at whatever threshold you've set — everything up to that number counts as regular hours, and everything above it counts as overtime. Change the default 40 to match your specific workplace or state rule, or turn overtime off to see one combined total instead. If you just need to calculate overtime pay for a set number of hours, try our Overtime Pay Calculator.
Do unpaid breaks count as work hours?
No — unpaid breaks should be subtracted before calculating pay. Enter your break length in the Break field and turn on Deduct Breaks, and the calculator removes that time automatically. If your entered times already exclude the break, turn Deduct Breaks off so it isn't subtracted twice.
Is this calculator really free, and is my data saved anywhere?
Yes, it's completely free with no signup. Nothing you enter is saved or sent anywhere — all calculations run locally in your browser and disappear when you refresh or close the page. Use the Print, Email, or Download buttons to save a copy before you leave.
Reviewed by the Pay & Time Hub team for accuracy against current U.S. federal overtime and timekeeping rules (FLSA).