เครื่องบวกลบเวลา

วิธีใช้เครื่องคิดเลขนี้

1. ป้อนStart Time
2. ป้อนOperation
3. ป้อนHours
4. ป้อนMinutes
5. คลิกปุ่มคำนวณ
6. อ่านผลลัพธ์ที่แสดงด้านล่างเครื่องคิดเลข

How to Add and Subtract Time

Adding or subtracting time requires working in a base-60 system for minutes and a base-24 system for hours. Unlike regular arithmetic, 75 minutes becomes 1 hour 15 minutes, and adding 3 hours to 22:00 wraps around to 01:00 the next day.

This calculator handles all wrapping automatically — so adding 5 hours to 22:30 correctly gives 03:30, not 27:30.

Common Use Cases for Time Calculation

Time addition and subtraction is useful for: scheduling meetings across time zones, calculating shift end times, figuring out arrival times, meal planning and cooking timers, and sports timing.

For example, if a flight departs at 14:45 and takes 7h 20m, it arrives at 22:05. Or if your shift starts at 07:00 and lasts 8.5 hours, it ends at 15:30.

24-Hour vs 12-Hour Time Format

This calculator uses 24-hour (military) time format. To convert: PM hours add 12 (3:00 PM = 15:00). 12:00 PM = 12:00. 12:00 AM = 00:00. Midnight wraps from 23:59 to 00:00.

For crossing midnight, the result will correctly wrap to the early hours of the next day.