Date Calculator
A date calculator performs arithmetic on calendar dates: it finds the exact difference between two dates in years, months, and days, or adds and subtracts a chosen amount of days, weeks, months, or years from a starting date. This free tool handles leap years and month-length differences automatically, so results are always accurate.
How to calculate dates
- Choose a mode: date difference, or add/subtract time.
- For a difference, enter a start date and an end date to see the span in years, months, and days.
- To add or subtract, enter a start date plus the number of days, weeks, months, or years.
- Read the result instantly. Leap years and month lengths are handled automatically.
Frequently Asked Questions
What calculations can the date calculator perform?
Our date calculator has two main functions: it can add or subtract a specific number of days, weeks, months, or years from a date, and it can calculate the exact time span (in years, months, days) between two dates.
Does the calculator account for leap years?
Yes, the date calculator correctly handles leap years, including the century rule (years divisible by 100 are not leap years unless they're also divisible by 400). This ensures accurate calculations even across leap year boundaries.
How are months handled when adding or subtracting time?
When adding or subtracting months, the calculator attempts to maintain the same day of the month. If the target month has fewer days than the original day, it will adjust to the last day of the target month (e.g., January 31 + 1 month becomes February 28/29).
Is the date difference inclusive or exclusive?
The date difference calculation can be toggled between inclusive (counting both the start and end dates) and exclusive (counting only days between start and end) modes. The default is exclusive, which calculates the exact number of full days between two dates.
Can I calculate business days or weekdays only?
Currently, the calculator computes calendar days, including weekends and holidays. For business day calculations, you would need to use the results as an estimate and adjust for weekends and holidays manually.
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