Free · Browser-Based · Time Math

Time Duration Calculator

Add and subtract time, calculate time difference between two clock values, and estimate end times for scheduling, shifts, and travel.

Mode

Start time

End time / base time

Duration (HH:MM)

Time summary

🎯 Common Use Cases

Calculate shift lengths

Find meeting or travel end times

Subtract breaks from schedules

Compare two clock times quickly

How should I enter duration?

Use HH:MM format such as 02:30 for two hours and thirty minutes.

Does it handle overnight times?

Yes. Difference mode treats an end time earlier than the start time as the next day.

Is this local only?

Yes. All calculations run in your browser.