Subtract a number of days from a starting date to find the resulting date and day of the week.
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This tool takes your starting date and moves backward by the exact number of days you specify, automatically handling month and year boundaries and leap years, then reports the resulting calendar date and its day of the week.
This is useful for finding a date a certain number of days before an event, calculating when to start a task to meet a deadline, or figuring out a past date, such as '90 days before my due date' or a project's required start date.
Subtracting 90 days from July 30, 2026 gives May 1, 2026, a Friday, correctly stepping backward across the boundaries of June and July (30 and 31 days respectively) without any manual month-by-month arithmetic.
Confusing calendar days with business days, subtracting 90 days includes weekends in that count, if you specifically need '90 business days before,' that's a different calculation than this tool performs.
Assuming the resulting day of the week follows a simple pattern, unless the number of days subtracted is a multiple of 7, the result lands on a different weekday than the start date.
Mixing up which direction is 'before' when planning backward from a deadline, double-check that subtracting (not adding) is actually what your specific planning scenario calls for.
Yes, you can subtract any number of days, including spans of multiple years, the calculator handles leap years automatically.
Use our Add Days Calculator to move a date forward by a number of days instead.
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