Hours Calculator - Add & Subtract Time
Add Hours and Minutes
Subtract Hours and Minutes
Calculate Time Between Two Times
Expert Tips for Time Calculations
Converting Time Formats
Hours to Decimal: Essential for UK payroll systems. Formula: Hours + (Minutes ÷ 60). Examples:
- 7h 30m = 7.5 hours (7 + 30/60)
- 8h 45m = 8.75 hours (8 + 45/60)
- 6h 15m = 6.25 hours (6 + 15/60)
Decimal to Hours:Minutes: Multiply decimal portion by 60. Example: 7.75 hours = 7h 45m (0.75 × 60 = 45 minutes).
UK Work Hours Best Practices
- Track breaks separately: Most UK lunch breaks are unpaid. If working 9am-5pm with 1-hour lunch, log 7 hours worked (not 8).
- Round to nearest 15 minutes: Many UK employers use quarter-hour rounding for timesheet accuracy.
- Document overtime clearly: Note regular hours vs overtime hours for correct pay calculation (often 1.5x rate).
- Weekly hour limits: UK maximum is 48 hours/week average. Use this calculator to track compliance.
Time Calculation Shortcuts
Quick 24-hour conversion:
- PM times: Add 12 (2:00 PM = 14:00, 5:30 PM = 17:30)
- Exception: 12:00 PM = 12:00 (noon), 12:00 AM = 00:00 (midnight)
Overnight calculations: If end time is earlier than start time, add 24 hours to end time. Example: 10 PM to 2 AM = 22:00 to 26:00 = 4 hours.
Common Time Calculation Mistakes to Avoid
1. Decimal Hour Confusion
Wrong: Thinking 1.5 hours = 1 hour 50 minutes
Right: 1.5 hours = 1 hour 30 minutes (0.5 × 60 = 30 minutes)
Why it matters: This error causes incorrect payroll calculations and timesheet submissions in UK companies.
2. Forgetting Minute Overflow
Wrong: 2h 40m + 1h 30m = 3h 70m
Right: 2h 40m + 1h 30m = 4h 10m (70 minutes = 1h 10m)
Rule: Always convert minutes over 60 to hours.
3. AM/PM Mix-ups
Confusing points:
- 12:00 PM is midday/noon (not midnight)
- 12:00 AM is midnight (not midday)
- 12:30 PM is afternoon (12:30, not 00:30)
UK solution: Use 24-hour format (common in transport, healthcare) to eliminate confusion.
4. Ignoring Unpaid Breaks
Wrong: Working 9am-5pm = 8 hours pay
Right: Working 9am-5pm with 1-hour unpaid lunch = 7 hours pay
UK law: 20-minute break required after 6 hours work (usually unpaid unless contract specifies otherwise).
5. Incorrect Rounding for Payroll
Wrong: 7h 45m entered as 7.45 hours in payroll system
Right: 7h 45m = 7.75 hours (45 ÷ 60 = 0.75)
Impact: Worker loses 30 minutes pay per occurrence (7.75 - 7.45 = 0.3 hours).
UK Working Time Regulations
The Working Time Regulations 1998 protect UK workers from excessive hours and ensure adequate rest periods.
Maximum Working Hours
48-hour weekly limit: Workers cannot be required to work more than 48 hours per week on average (calculated over 17 weeks).
Opt-out option: Workers can voluntarily opt out in writing, but employers cannot force this. Opt-out doesn't apply to certain jobs (transport workers, junior doctors).
Rest Entitlements
- Daily rest: 11 consecutive hours between working days
- Weekly rest: 24 hours per week (or 48 hours per fortnight)
- Breaks: 20-minute break when working more than 6 hours
Night Work Limits
Night workers (working at least 3 hours between 11 PM - 6 AM) limited to average 8 hours per 24-hour period. Employers must offer health assessments.
Annual Leave
Statutory minimum: 5.6 weeks (28 days for full-time workers). This includes bank holidays unless employer gives additional leave. Part-time workers receive pro-rata entitlement.
Who's Covered?
Protected: Employees, workers, agency workers, casual workers.
Exceptions: Self-employed, managing executives, armed forces (partial exemptions), emergency services (modified rules).
Tracking Compliance
Use this hours calculator to monitor your weekly hours. If regularly exceeding 48 hours without opt-out, or not receiving required breaks/rest, contact ACAS (Advisory, Conciliation and Arbitration Service) or your trade union.
How to Use the Hours Calculator
Adding Hours and Minutes
- Select the "Add Hours" tab
- Enter first time period (hours and minutes)
- Enter second time period
- Click "Calculate Total Time"
- Results show total in both hours:minutes and decimal format
Use cases: Combining multiple work shifts, totaling project time, summing travel durations.
Subtracting Time
- Select the "Subtract Hours" tab
- Enter starting time amount
- Enter time to subtract
- Click "Calculate Time Difference"
- See remaining time
Use cases: Calculating time after breaks, remaining work hours, time left until deadline.
Calculating Time Between Two Clock Times
- Select the "Time Difference" tab
- Enter start time (use time picker)
- Enter end time
- If overnight shift, check "End time is next day"
- Click "Calculate Duration"
Use cases: Work shift duration, meeting length, travel time, overnight work calculations.
Understanding Results
Calculator provides:
- Hours:Minutes format: Easy to read (e.g., 7h 30m)
- Decimal hours: For payroll systems (e.g., 7.5 hours)
- Total minutes: Useful for detailed tracking
Frequently Asked Questions
How do I add hours and minutes together?
To add hours and minutes: (1) Add hours together first, (2) Add minutes together, (3) If minutes exceed 60, convert to hours (60 minutes = 1 hour). Example: 3h 45m + 2h 30m = 5h 75m = 6h 15m. Common UK uses: Combining multiple work shifts, Total study time across subjects, Travel time with connections, Project time tracking. Use this calculator for automatic conversion and accurate results.
How do I subtract hours and minutes?
To subtract time: (1) Convert both times to minutes, (2) Subtract smaller from larger, (3) Convert back to hours and minutes. Example: 5h 15m - 2h 45m = 315 minutes - 165 minutes = 150 minutes = 2h 30m. If subtracting across midnight: Add 24 hours to end time first. Example: End 1:00 AM, Start 10:00 PM = 25:00 - 22:00 = 3 hours. UK applications: Calculating actual work time (start to finish minus breaks), Remaining time until deadline, Duration of meetings or events.
How many hours is full-time work in the UK?
UK full-time hours: Typically 35-40 hours per week, with 37.5 hours most common for office jobs. UK Working Time Regulations: Maximum 48 hours per week average (calculated over 17 weeks), 11 hours rest between shifts, 24-hour rest period per week. Common patterns: Standard: 9am-5pm, 5 days = 37.5h (7.5h/day with 30min unpaid lunch), Extended: 8am-6pm, 4 days = 40h, Shift work: 12-hour shifts, variable patterns. Part-time: Under 35 hours/week. Overtime: Hours beyond contracted hours, often paid at 1.5x rate (time and a half). Use hours calculator to track compliance with Working Time Regulations.
How do I calculate time differences across AM/PM?
Calculate time across AM/PM boundaries: (1) Convert to 24-hour format (PM hours: add 12), (2) Calculate difference normally. Example: 9:30 AM to 2:45 PM. Convert: 9:30 to 14:45 (2 PM + 12 = 14:00). Calculate: 14:45 - 9:30 = 5h 15m. Across midnight example: 10:30 PM to 1:15 AM. Convert: 22:30 to 25:15 (1:15 AM next day = 24:00 + 1:15). Calculate: 25:15 - 22:30 = 2h 45m. UK 24-hour time: Common in transport (train/bus timetables), healthcare (hospital shifts), military. 12-hour time: Common in everyday conversation, some workplaces. This calculator handles both formats automatically.
What are common time calculation mistakes?
Common time calculation errors: (1) Decimal confusion: 1.5 hours = 1h 30m (NOT 1h 50m). Excel shows 1.5h correctly, but manual conversions often wrong. (2) Forgetting minute overflow: 2h 40m + 1h 30m = 4h 10m (not 3h 70m). Minutes over 60 must convert to hours. (3) AM/PM errors: 12:30 PM is afternoon (12:30), 12:30 AM is after midnight (00:30). 12 PM = noon, 12 AM = midnight. (4) Break time: If working 9am-5pm with 1h lunch, actual work time is 7 hours (not 8 hours). (5) Rounding incorrectly: 7h 45m is 7.75h (not 7.45h). Conversion: Minutes ÷ 60 = decimal hours. This calculator prevents all these mistakes with automatic conversions.
How do I convert hours to decimal format for payroll?
Convert hours:minutes to decimal hours for UK payroll: Formula: Hours + (Minutes ÷ 60) = Decimal hours. Examples: 8h 30m = 8 + (30÷60) = 8.5 hours, 7h 45m = 7 + (45÷60) = 7.75 hours, 6h 15m = 6 + (15÷60) = 6.25 hours, 9h 20m = 9 + (20÷60) = 9.33 hours. Quick reference: 15 min = 0.25h, 30 min = 0.5h, 45 min = 0.75h. UK payroll systems typically use decimal format: Employee works 37.5h at £15/hour = £562.50. HMRC requirements: Record actual hours worked, Include all overtime, Ensure National Minimum Wage compliance (total pay ÷ total hours ≥ minimum wage). This calculator shows both formats (hours:minutes and decimal) for easy payroll entry.
Do UK employers have to pay for break times?
UK break time rules: Workers' legal entitlement: 20-minute break if working more than 6 hours (unpaid unless contract states otherwise), 11 hours rest between shifts, 24-hour rest period per week. Paid vs unpaid breaks: Legal minimum breaks are usually unpaid, Many employers offer paid breaks (check contract), Lunch breaks typically unpaid (30-60 minutes), Short breaks (5-15 minutes) often paid. Example: Working 9am-5pm (8 hours) with 1-hour lunch = 7 hours paid work. Calculating work hours: Include all time 'at employer's disposal', Exclude unpaid lunch breaks, Include paid coffee breaks, Include time spent traveling between sites during workday (not commute). Some sectors have different rules: Healthcare, emergency services may have on-call paid breaks, Teaching has PPA time (planning, preparation, assessment). Always check employment contract for specific break entitlements and pay.
How does the UK Working Time Directive affect my hours?
UK Working Time Regulations 1998 (retained from EU Working Time Directive): Maximum hours: 48-hour average per week (calculated over 17 weeks), Can opt out voluntarily in writing (but employer cannot force opt-out), Opt-out doesn't apply to certain jobs (lorry drivers, airline staff). Rest requirements: 11 consecutive hours rest per 24-hour period, 24-hour rest per week (or 48 hours per fortnight), 20-minute break if working 6+ hours. Annual leave: Minimum 5.6 weeks (28 days for full-time workers), Includes bank holidays unless employer gives additional leave, Part-time: Pro-rata entitlement. Night workers: Maximum 8 hours per 24-hour period average, Health assessments required. Exceptions: Self-employed, Managing executives/family workers, Armed forces, Emergency services (partial exemptions). Penalties for employers: Employment tribunal claims, Workers can refuse to work excessive hours, HSE enforcement action. Track your hours with this calculator to ensure compliance and discuss concerns with employer or ACAS.
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Pro Tips for Accurate Results
- Double-check your input values before calculating
- Use the correct unit format (metric or imperial)
- For complex calculations, break them into smaller steps
- Bookmark this page for quick future access
Understanding Your Results
Our Hours Calculator provides:
- Instant calculations - Results appear immediately
- Accurate formulas - Based on official UK standards
- Clear explanations - Understand how results are derived
- 2025/26 updated - Using current rates and regulations
Common Questions
Is this calculator free?
Yes, all our calculators are 100% free to use with no registration required.
Are the results accurate?
Our calculators use verified formulas and are regularly updated for accuracy.
Can I use this on mobile?
Yes, all calculators are fully responsive and work on any device.