Calculate time differences, add/subtract hours, and convert time zones.
12:01:08
AM
MON, AUG 31, 2026
Modes Label
New York-4
New York
08:01 PM
Sun, Aug 30
London+1
London
01:01 AM
Mon, Aug 31
Tokyo+9
Tokyo
09:01 AM
Mon, Aug 31
About this calculator
Overview Title
Clock calculators help with time arithmetic: adding/subtracting hours, finding time differences, and converting between time zones. Essential for scheduling, travel planning, and coordinating across regions.
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Pro Tips
24-hour format avoids AM/PM confusion.
Time zones change every 15° of longitude (1 hour).
DST (Daylight Saving Time) affects many regions seasonally.
UTC is the standard reference for all time zones.
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Fun Facts
"There are 24 standard time zones worldwide."
"China uses one time zone despite spanning 5 geographically."
"International Date Line runs through Pacific Ocean."
"Atomic clocks lose less than 1 second per million years."
