Date Calculator

Date add/subtract rules

This tool starts from a base date and applies years, months, weeks, and days in one calculation.

Month and year movement follows calendar meaning, so adding one month from a late-month date lands on the closest valid date in the target month.

How to read the result

Positive movement points to a future date and negative movement points to a past date. The result keeps the original base date visible for comparison.

Use the date difference or D-Day tools when you need to compare the result with another date.

Examples

Anniversary planning

Add 100 days or one year to a base date to find a milestone date.

Billing and expiry dates

Add months or subtract days to check renewal, payment, or cancellation windows.

Limits

• The tool calculates calendar dates only, not time-of-day movement.
• Business-day skipping belongs in the workday calculator.
• URL state stores the numeric inputs used for the calculation.

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