KALKSY

Add/Subtract Time Calculator

Add or subtract hours and minutes from a given time instantly.

Select a starting date and time

Date
Time::
HoursMinutesSeconds
Result (Date):

3/13/2026

Result (Time):

16:37:38

Time Arithmetic Explained ⏰

Time calculators adjust a starting time by adding or subtracting hours and minutes.

They are widely used for scheduling, shift planning, and travel calculations.

Key Facts

  • Crossing midnight changes the calendar date.
  • 24-hour time reduces ambiguity.
  • Time math may require carrying over 60 minutes into hours.

Formulas

  • Time Adjustment Formula
    New Time = Start Time ± Duration - Adds or subtracts time units while adjusting for overflow.

Example

  • 10:30 PM + 3 hours = 1:30 AM (next day).
  • 2:15 PM − 45 minutes = 1:30 PM.