Date Calculator

Add or subtract a number of days from any calendar date.

Date Calculator helps you add or subtract days from a date. Enter start date and days to add, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Add days calculator does Date Calculator is built for dates, durations, ages, and schedules. Add or subtract days from a date. You enter start date and days to add, then Simple Calculators computes the result instantly. Calendar math follows common civil-calendar rules used in everyday planning. How the math works Uses the local calendar. Crossing month and leap-day boundaries is handled by the Date object. The formula: New date = start date + number of days. Use a negative number of days to go back in time.