Time Calculator
Add and subtract time durations
Time Calculator
How to Use
- Enter hours, minutes, and seconds for both time values
- Click Add Times to sum the durations
- Click Subtract Times to find the difference
- Result handles overflow (e.g., 90 minutes = 1h 30m)
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About Time Calculator
A time calculator is an essential tool for performing mathematical operations with time values—adding hours to find end times, subtracting durations to calculate elapsed time, multiplying time by quantities, or converting between different time units. Unlike regular calculators that work with decimal numbers, time calculations require special handling because time uses base-60 (60 seconds in a minute, 60 minutes in an hour) rather than base-10 mathematics. Our time calculator handles the complex conversions automatically, allowing you to add 2 hours 45 minutes to 3:30 PM, subtract 45 minutes from a time, multiply 1 hour 30 minutes by 5, or convert between hours, minutes, and seconds effortlessly. This tool is invaluable for project time tracking, scheduling calculations, payroll and timesheet processing, travel time estimation, cooking timer calculations, and any scenario requiring precise time arithmetic. Whether you're a project manager calculating task durations, an employee tracking billable hours, a student planning study time, a traveler calculating arrival times, or anyone working with time-based calculations, the time calculator eliminates the error-prone process of manual time math. The tool supports 12-hour and 24-hour time formats, handles times across midnight, accounts for AM/PM conversions, and presents results in multiple formats for convenience and clarity.
Key Features
Add and Subtract Time
Add hours, minutes, and seconds to any time, or subtract durations to find earlier times. For example, add 2 hours 30 minutes to 3:45 PM to get 6:15 PM, or subtract 45 minutes from 10:00 AM to get 9:15 AM. Perfect for scheduling and timeline calculations.
Time Duration Calculations
Calculate the duration between two times. Enter start time and end time to see exactly how many hours, minutes, and seconds elapsed. Handles times across midnight (like 11 PM to 1 AM showing 2 hours), perfect for shift work and overnight durations.
Multiply and Divide Time
Multiply time values by numbers for repetitive tasks or rate calculations. For example, multiply 1.5 hours by 8 days to get total weekly hours. Divide time into equal parts for breaking tasks into segments or calculating per-unit time allocations.
12-Hour and 24-Hour Formats
Work with either 12-hour format (with AM/PM) or 24-hour format (military time). Switch between formats instantly. The calculator automatically handles AM/PM conversions and displays results in your preferred format, accommodating regional preferences.
Multiple Time Units
Input and output in hours, minutes, seconds, or any combination. Enter time as hours:minutes:seconds, decimal hours, total minutes, or total seconds. Results are displayed in multiple formats simultaneously for convenience—see both '2.5 hours' and '2 hours 30 minutes'.
Decimal to Time Conversion
Convert decimal hours (like 7.5 hours) to hours:minutes format (7:30), or vice versa. Essential for payroll calculations where time is tracked decimally but needs to be understood in standard time format. Handles fractional hours accurately.
Batch Calculations
Perform multiple time calculations at once. Add several time periods together (like adding daily work hours to get weekly total), or calculate multiple endpoints from one start time. Save time when working with many time values.
Export Results
Copy calculated results to clipboard or export calculation history. Perfect for documentation, timesheets, reports, or sharing results with others. Export includes both the calculation inputs and results for complete records.
How to Use the Time Calculator
Select your calculation type from the mode dropdown: 'Add Time', 'Subtract Time', 'Duration Between Times', 'Multiply Time', or 'Convert Time'
Choose the operation that matches what you need to calculate.
Enter your starting time or first time value
Use the time picker for convenience, or type directly in hours:minutes:seconds format. The calculator accepts various formats—3:30 PM, 15:30, 3.5 hours, 210 minutes.
Enter your second time value or duration, depending on your calculation type
For adding/subtracting, enter the duration. For duration calculations, enter the end time. For multiplication, enter the multiplier number.
Choose your time format preference: 12-hour with AM/PM, or 24-hour military time
The calculator displays results in your chosen format, automatically handling conversions between formats as needed.
Select output format preferences
Choose whether you want results in hours:minutes:seconds, decimal hours, total minutes, or all formats simultaneously. Different formats suit different use cases.
Click 'Calculate' to perform the time calculation
Results appear instantly showing the calculated time, along with any additional information like total hours, decimal representation, or alternative formats.
Review the detailed breakdown of your calculation
See step-by-step how the calculation was performed, including any carryovers (60 minutes → 1 hour) or borrowing in the arithmetic.
Copy results to clipboard or add to calculation history
For recurring calculations, save the calculation for quick access later. Export history for documentation or import into timesheets or reports.
Frequently Asked Questions
How do I calculate time across midnight?
The calculator automatically handles times that cross midnight. When calculating duration from 11 PM to 2 AM, it correctly shows 3 hours, not negative time. For times crossing midnight, ensure you specify AM/PM correctly in 12-hour format, or use 24-hour format where 23:00 (11 PM) to 02:00 (2 AM) is clearly understood as crossing midnight.
What's the difference between decimal hours and time format?
Time format uses hours:minutes:seconds (like 2:30 meaning 2 hours 30 minutes). Decimal hours expresses the same as a decimal number (2.5 hours). Decimal hours are common in payroll and billing systems because they're easier for calculations and databases. Time format is more intuitive for humans. Our calculator converts between both formats instantly.
Can I add more than two time values together?
Yes! Use the batch calculation feature or simply add times sequentially. Add the first two times, then add the result to the third time, and so on. Alternatively, enter multiple times separated by '+' signs, and the calculator sums them all at once. This is perfect for adding up daily work hours to get weekly totals.
How does the calculator handle seconds and milliseconds?
The calculator supports hours, minutes, and seconds. For most use cases, second precision is sufficient. If you need millisecond precision (for sports timing or scientific measurements), you can enter decimal seconds (like 45.123 seconds). Results can be displayed with decimal seconds for high-precision needs.
Can I calculate negative time or time before a starting point?
Yes, when subtracting time, if you subtract more than the starting amount, the result is negative (like subtracting 5 hours from 3 hours gives -2 hours). Negative results indicate how much earlier you need to start. This is useful for deadline calculations where you work backwards from a target time.
How do I convert minutes to hours and minutes?
Enter the total minutes in the calculator and select 'Convert' mode. For example, 150 minutes converts to 2 hours 30 minutes. The calculator automatically performs the division and shows results in standard time format. This is useful when you have total minutes from timers or trackers and need human-readable format.
Does the calculator handle time zones?
The basic time calculator performs arithmetic operations without time zone conversions. For time zone conversions (like 3 PM EST to PST), use a dedicated time zone converter tool. However, you can manually account for time zones by adding or subtracting the offset (like adding 3 hours when converting EST to PST).
Can I use this for calculating elapsed time on a stopwatch?
Yes! Enter your start time and end time in the 'Duration Between Times' mode to see elapsed time. The calculator shows duration in hours:minutes:seconds format, as well as total hours, total minutes, and total seconds. This is perfect for timing events, measuring task duration, or calculating elapsed time for any activity.
Use Cases
- Employee Time Tracking and Payroll: Calculate total work hours from time entries, determine overtime hours, or convert between decimal hours for payroll systems and time format for human readability. Add up daily hours to get weekly totals, subtract breaks from work periods, and ensure accurate payroll calculations.
- Project Time Management: Estimate task durations, calculate project timelines, determine resource allocation by time, and track actual vs estimated time. Project managers can add up task durations to estimate project completion, subtract elapsed time to find remaining time, and multiply hourly rates by time for budgeting.
- Travel and Schedule Planning: Calculate arrival times by adding travel duration to departure time, determine how much time between connecting flights, plan daily itineraries with multiple stops, and account for time zone changes. Perfect for trip planning, meeting scheduling, and logistics coordination.
- Cooking and Recipe Timing: Add up cooking times for multiple recipe steps to determine total preparation time, calculate when to start cooking to have food ready at specific time, or convert recipe times between hours and minutes for easier following.
- Billing and Time-Based Pricing: Calculate billable hours for clients, multiply hourly rates by worked time, add up time across multiple tasks or days for invoicing, and convert between time formats required by different billing systems. Essential for consultants, freelancers, and service providers.