Hours Calculator

About the Hours Calculator

An hours calculator determines exactly how many hours and minutes elapsed between two times — a task that sounds simple but is genuinely error-prone by hand because of the 60-minute hour, AM/PM transitions, and midnight crossings. Whether you need to calculate how many hours you worked this week for a timesheet, figure out the total time between two clock readings, add up multiple work sessions, or subtract a break from your total shift time, our free hours calculator handles every scenario instantly. It accepts both 12-hour (AM/PM) and 24-hour clock formats, handles overnight shifts that cross midnight automatically, deducts break time cleanly, and outputs results in both HH:MM format (hours and minutes) and decimal hours (essential for invoicing, where 7 hours 45 minutes = 7.75 hours multiplied by your rate). The tool is used daily by hourly employees verifying their pay stubs, freelancers and contractors creating accurate invoices, managers calculating team payroll, and anyone tracking time-based work. It is optimised for time-tracking conventions in the USA, Canada, UK, and Australia where overtime rules and pay period structures differ. For weekly calculations, it sums multiple daily totals and flags any day exceeding 8 hours, which is the standard overtime trigger in most jurisdictions.

How It Works

The calculation converts both start and end times to total minutes from midnight (0:00), subtracts to find elapsed minutes, then converts back to hours and minutes. Start 9:00 AM = 540 minutes from midnight. End 5:30 PM = 1,050 minutes. Difference = 1,050 - 540 = 510 minutes = 8 hours 30 minutes = 8.5 decimal hours. Overnight shift example: Start 10:00 PM (1,320 min), End 6:00 AM (360 min). Since end appears earlier than start, the calculator automatically adds 1,440 minutes (24 hours): 360 + 1,440 - 1,320 = 480 minutes = 8 hours. Break deduction: a 9:00 AM to 5:30 PM shift with a 45-minute lunch break = 510 - 45 = 465 minutes = 7 hours 45 minutes = 7.75 decimal hours. Weekly total: sum all daily net hours across 5 or 6 days; hours above 40 for the week are typically overtime at 1.5x in the USA under FLSA, or above 44 in most Canadian provinces.

Tips & Best Practices

• ✓Always record time in 24-hour format for internal calculations to eliminate AM/PM ambiguity — the most common source of hours calculation errors, particularly on overnight shifts.
• ✓US federal overtime law (FLSA): overtime pay at 1.5x the regular rate is required for non-exempt employees working more than 40 hours in a single workweek — not per day, per week. Some states have daily overtime rules (California requires 1.5x after 8 hours in a day).
• ✓For invoicing decimal hours: 7 hours 45 minutes = 7.75 hours. Multiply 7.75 by your hourly rate to get the exact invoice amount with no rounding disputes. Always present decimal hours on professional invoices.
• ✓UK working time regulations: workers are legally entitled to an uninterrupted 20-minute rest break for any shift over 6 hours. This break is typically unpaid and should be deducted from gross hours to calculate paid time.
• ✓Night shift cross-midnight detection: if your end time shows earlier than your start time (e.g., 10 PM to 6 AM), the calculator treats this as an overnight shift spanning two calendar days and adds 24 hours to the end time before calculating.
• ✓Biweekly payroll: track each individual week separately for overtime compliance before summing for the two-week pay period. Overtime is calculated per workweek, not per pay period — a 50-hour week and 30-hour week in the same biweekly period means 10 hours of overtime pay owed.
• ✓Australia penalty rates: casual employees and those working weekends or public holidays may be entitled to loading of 125-250% of their standard rate — ensuring accurate hours tracking is essential before applying the correct rate.
• ✓International students on F-1 visas (USA) are limited to 20 hours of on-campus work per week during academic terms. The hours calculator helps verify compliance with this condition to protect visa status.

Who Uses This Calculator

Hourly employees use the hours calculator weekly to verify that the hours on their pay stub match the hours they actually worked — discrepancies are common and should be flagged to payroll immediately. Freelancers and independent contractors use it to generate accurate billing hours for client invoices, eliminating the rounding disputes that damage professional relationships. Small business owners and office managers calculate weekly payroll hours for each employee before submitting to payroll processors or calculating cheques manually. Healthcare workers, restaurant staff, retail employees, and security personnel — all groups with irregular shift patterns — use it to track exact daily hours including paid breaks and confirm that overtime thresholds have or have not been crossed. Project managers sum team member hours across multiple work sessions to calculate project labour costs for budget tracking and client billing reconciliation. Students working part-time under visa or scholarship hour restrictions use the calculator to ensure they remain in compliance with their specific weekly hour limits. Personal trainers, tutors, and other session-based service providers use it to calculate total billable time across multiple clients and sessions in a week.