Time Calculator

Time Difference Calculator

Calculate the duration between two times or dates with precision.

• Input: Start time and end time in HH:MM:SS format
• Output: Total duration in hours, minutes, seconds
• Formats: Breakdown in days, hours, minutes, seconds
• Conversions: Duration in decimal hours, total minutes, total seconds
• Auto-handles: Times that cross midnight

Time Addition/Subtraction

Add or subtract time periods from a given time accurately.

• Add Time: Calculate future times by adding hours, minutes, seconds
• Subtract Time: Calculate past times by subtracting duration
• Handles: Time overflow (e.g., 90 minutes = 1h 30m)
• Multi-day: Add/subtract days along with time

Work Hours Calculator

Calculate total work hours between times for payroll and scheduling.

• Clock in/out: Enter start and end times
• Lunch breaks: Calculate work hours excluding breaks
• Weekly hours: Use Add Time to sum multiple days
• Overtime: Identify hours over 40 per week

Calculating Time Difference

Example: Calculate work hours

1. Enter Start Time: Format: HH:MM:SS (e.g., 09:00:00)
2. Enter End Time: Format: HH:MM:SS (e.g., 17:30:00)
3. Calculate: Click "Calculate Duration"

Result: 8 hours 30 minutes

Adding Time

Example: Time 4.5 hours from now

1. Enter Base Time: Current time (e.g., 14:30:00)
2. Enter Time to Add: Hours: 4, Minutes: 30
3. Calculate: Click "Calculate Result"

Result: 19:00:00 (7:00 PM)

Converting Time Units

Example: Convert 500 minutes to hours

Use the Time Difference tab with start time 00:00:00 and end time after calculating total minutes, or manually divide: 500 ÷ 60 = 8.33 hours or 8 hours 20 minutes

Example 1: Work Hours Calculation

Scenario: Calculate daily work hours with lunch

• Clock in: 9:00 AM
• Lunch start: 12:00 PM
• Lunch end: 1:00 PM
• Clock out: 5:30 PM

Calculation:

• Morning: 9:00 AM to 12:00 PM = 3 hours
• Lunch: 12:00 PM to 1:00 PM = 1 hour (break)
• Afternoon: 1:00 PM to 5:30 PM = 4.5 hours
• Total work hours: 3 + 4.5 = 7.5 hours

Example 2: Time Zone Difference

Scenario: Calculate duration between time zones

• New York: 3:00 PM EST
• London: 8:00 PM GMT (5-hour difference)

Meeting duration:

• Start: 3:00 PM New York (8:00 PM London)
• End: 4:30 PM New York (9:30 PM London)
• Duration: 1 hour 30 minutes

Example 3: Project Duration

Scenario: Calculate project completion time

• Start date: January 15, 2025 at 9:00 AM
• Duration: 120 hours

End date calculation:

• 120 hours = 5 days (24 × 5 = 120)
• End date: January 20, 2025 at 9:00 AM

With work days only (8 hours/day):

• 120 hours ÷ 8 hours per day = 15 work days

Adding Time

Basic addition:

2 hours 30 minutes + 1 hour 45 minutes = 3 hours 75 minutes = 4 hours 15 minutes (60 minutes = 1 hour)

With seconds:

1:30:45 + 2:45:30 = 3:75:75 = 4:16:15 (carry excess)

Subtracting Time

Basic subtraction:

5 hours 30 minutes - 2 hours 45 minutes = 2 hours 45 minutes (borrow 1 hour = 60 minutes)

From clock time:

Current time: 3:15 PM - Subtract: 8 hours = 7:15 AM (previous day)

Converting Time Units

Minutes to decimal hours:

• 75 minutes = 75/60 = 1.25 hours
• 30 minutes = 30/60 = 0.5 hours
• 45 minutes = 45/60 = 0.75 hours

Decimal hours to hours:minutes:

• 1.5 hours = 1 hour 30 minutes
• 2.75 hours = 2 hours 45 minutes
• 8.33 hours = 8 hours 20 minutes

12-Hour Clock (AM/PM)

Format: HH:MM:SS AM/PM

• 09:00:00 AM = 9:00 AM
• 12:00:00 PM = 12:00 PM (noon)
• 12:00:00 AM = 12:00 AM (midnight)
• 03:30:45 PM = 3:30:45 PM

Converting to 24-hour: AM times: Same (except 12 AM = 0), PM times: Add 12 (except 12 PM = 12)

24-Hour Clock (Military)

Format: HH:MM:SS (00:00:00 to 23:59:59)

• 09:00 = 9:00 AM
• 12:00 = 12:00 PM (noon)
• 15:30 = 3:30 PM
• 23:59 = 11:59 PM
• 00:00 = 12:00 AM (midnight)

Decimal Hours

Format: HH.HH

• 8.00 = 8:00 (8 hours 0 minutes)
• 8.25 = 8:15 (8 hours 15 minutes)
• 8.50 = 8:30 (8 hours 30 minutes)
• 8.75 = 8:45 (8 hours 45 minutes)

Conversion: Minutes / 60 = Decimal portion (e.g., 45/60 = 0.75)

Work and Payroll

Weekly hours calculation example:

Total: 42 hours | Regular (40 hours): 40 | Overtime: 2 hours

Gross pay (at $20/hour): Regular: 40 × $20 = $800 | Overtime: 2 × $30 = $60 | Total: $860

Project Management

Task duration:

• Start: Week 1, Day 1
• Duration: 120 hours (3 work weeks)
• End: Week 4, Day 2

Critical path example:

• Task A: 40 hours (Week 1)
• Task B: 60 hours (Week 2-3)
• Task C: 20 hours (Week 3)
• Total project: 120 hours

Calculating Duration Across Midnight

Example: 11:00 PM to 2:00 AM

Method 1: Add 24 hours to end time

End: 2:00 AM + 24 = 26:00 | Duration: 26:00 - 23:00 = 3 hours

Method 2: Calculate to midnight, then add

11:00 PM to midnight: 1 hour | Midnight to 2:00 AM: 2 hours | Total: 3 hours

Leap Years

Rules:

1. Divisible by 4 = leap year
2. Except centuries not divisible by 400

Examples: 2024: Leap year (divisible by 4) | 2023: Not leap year | 2000: Leap year (divisible by 400) | 1900: Not leap year (century not divisible by 400)

Business Days

Excluding weekends:

5-day work week: Monday to Friday, excludes Saturday and Sunday

Example: Start: Wednesday, Duration: 7 calendar days = 5 business days, End: Following Tuesday

Holidays: Varies by country (US: ~10 federal holidays, UK: ~8 bank holidays)

Problem 1: Calculate Work Hours

Solution:

• Monday: 8.5h - 1h = 7.5h
• Tuesday: 9h - 1h = 8h
• Wednesday: 8h - 0.5h = 7.5h
• Thursday: 9.5h - 1h = 8.5h
• Friday: 8.5h - 0.5h = 8h

Weekly total: 39.5 hours | Regular: 39.5 | Overtime: 0 hours

Problem 2: Time Addition

Calculate: 6h 45m + 3h 30m + 2h 15m

Solution:

Hours: 6 + 3 + 2 = 11 hours | Minutes: 45 + 30 + 15 = 90 minutes = 1 hour 30 minutes | Total: 12 hours 30 minutes

Problem 3: Convert Minutes to Hours

Convert: 375 minutes to hours and minutes

Solution:

375 ÷ 60 = 6.25 hours = 6 hours + 0.25 × 60 minutes = 6 hours 15 minutes