Time Duration Calculator
Display Settings
Start Time
Set to Now
End Time
Set to Now
--:--:--
Enter start and end times to calculate the duration.
| Decimal Hours | -- |
| Total Minutes | -- |
| Total Seconds | -- |
| Total Milliseconds | -- |
How to Use This Calculator
Enter Start & End Times
Input the hours and minutes for both the start and end points. You can also use the "Set to Now" buttons for convenience.
Select AM/PM
Ensure the correct AM or PM value is selected for each time. This is crucial for calculating the time duration accurately, especially for periods crossing noon or midnight.
Calculate the Duration
Click the "Calculate Duration" button. The result will appear below in multiple formats, including a detailed breakdown table.
Calculation Breakdown
Input Time
(e.g., 2:30 PM)
(e.g., 2:30 PM)
→
24-Hour Format
(14:30)
(14:30)
→
Total Milliseconds
(52,200,000)
(52,200,000)
→
Final Duration
(HH:MM:SS)
(HH:MM:SS)
Practical Use Cases
Project Management
Log start and end times for tasks to calculate billable hours accurately.
Event Planning
Calculate the duration of speeches, breaks, and sessions to build a precise event timeline.
Scientific Research
Measure the exact time duration of experiments for data logging and analysis.
Time Duration vs. Time Point
| Concept | Description | Example |
|---|---|---|
| Time Duration | A measure of the time elapsed between two points. It has a length but no fixed position in time. | "2 hours and 15 minutes" |
| Time Point | A specific, single moment in time. | "4:30 PM on Tuesday" |
Calculating Overnight Time Durations
This calculator automatically detects durations that cross midnight. For example, calculating from 10:00 PM to 2:00 AM will correctly result in a 4-hour duration. The logic adds 24 hours if the end time is numerically earlier than the start time.
Tips for Precision
Always double-check that AM/PM is set correctly. It's the most common source of error in time duration calculation.
For 12 o'clock, use "12". The calculator correctly interprets "12:00 AM" as the start of the day (midnight).
Use the "Set to Now" button for an accurate starting or ending point without manual entry.
Core Features
Overnight Calculation
Detailed Breakdown
"Set to Now" Buttons
Copy to Clipboard
Frequently Asked Questions
Does this calculator handle time zones?
▼
No. This tool calculates the duration between two times assuming they are in the same time zone. For calculations across different time zones, you must convert one of the times first.
What is the maximum time duration I can calculate?
▼
The calculator is designed for durations up to 24 hours. If a start and end time result in a duration longer than 24 hours (e.g., 2:00 PM to 2:00 PM), it will be treated as either 0 or 24 hours. For multi-day calculations, a Date Time calculator is more appropriate.