Add or subtract days
Add days, weeks, months or years to a date, optionally counting business days only.
2026-10-26
How it works
Adding days is simple counting. Adding months is not, because months have different lengths — so the answer depends on a convention.
Month-end clamping
31 January plus one month is 28 February (29 in a leap year), not 3 March. This tool clamps to the last valid day of the target month, which is what banks, subscriptions and legal deadlines generally do. The consequence is that the operation is not reversible: 31 Jan + 1 month − 1 month gives 28 Jan.
Business days
With business days selected, weekends are skipped entirely — Friday plus one business day is Monday. Public holidays are not included, since they depend on your country; the business days calculator lets you supply them.
Common uses
“90 days from today” for notice periods and returns windows; “6 months from signing” for contract terms; “−14 days” for working backwards from a deadline.