📅 Calendar Calculator

Our calendar calculator is highly accurate for standard Gregorian calendar calculations. It properly handles leap years, varying month lengths, and business day calculations. However, for historical dates before 1582 (Gregorian calendar adoption) or specialized calendar systems, results may vary.

Yes, you can enable the "Business Days Only" option to exclude weekends (Saturday and Sunday). Additionally, you can specify custom holidays in YYYY-MM-DD format, separated by commas, to exclude them from the calculation.

When including the end date, both the start and end dates are counted in the calculation. When excluding the end date, only the start date is counted. For example, from Jan 1 to Jan 3 including end date = 3 days, excluding end date = 2 days.

The calculator automatically detects leap years and adjusts February to have 29 days instead of 28. This ensures accurate calculations when adding/subtracting time periods or calculating intervals that span leap years.

Yes, you can enter negative values in any time unit field to subtract that amount from the starting date. Alternatively, you can use the dedicated subtraction mode for clearer operation indication.

The calculator uses your browser's default date format for input fields. Results are displayed in a readable format (Month DD, YYYY). The calculator internally handles various date formats and ensures consistent calculations.

The calculator supports dates from year 1 to year 9999. However, for dates before 1582, please note that the Gregorian calendar rules are applied retroactively, which may not reflect historical calendar systems used at that time.

The basic calculator works with calendar dates only. For time zone considerations, you would need to manually adjust your input dates to the desired time zone before calculation.