Date Add & Subtract Calculator
Add or subtract years, months, weeks and days from any date, with correct end-of-month handling.
Formula
calendar-aware, clamping to the end of month rather than rolling over
Tips
- Years and months are applied before days, which is the convention contracts and statutes assume.
- End-of-month is clamped, not rolled: 31 January plus one month is 28 or 29 February, not 3 March.
- For deadlines counted in working days rather than calendar days, use the business days calculator instead.
Frequently asked questions
Why clamp rather than roll over?
Because "one month after 31 January" almost always means the end of February in practice — rent dates, notice periods, subscription renewals. Rolling into March surprises people and is rarely what a contract intends.