Add or Subtract Days
A date ± days — the exact date it lands on, weekday included.
How this is calculated
Day arithmetic on the real calendar — leap years included, no "30-day month" approximations. Days are the unambiguous unit (months vary in length, which is why "one month later" starts arguments and "30 days later" doesn't). The everyday uses: notice periods, visa windows, returns deadlines, medication courses, and "90 days from signature" contract clauses.
Frequently asked questions
What is 90 days from today?
Set the start to today (the default) and days to 90 — the result shows the exact date and its weekday. Month lengths and leap years are handled by walking the real calendar, so the answer matches what a diary would give you.
Can I subtract days instead?
Yes — flip the Add/Subtract toggle, or think of it as negative days. "45 days before the deadline" is exactly what the subtract direction answers.
Why does the weekday matter?
Because deadlines that land on weekends usually roll. The result always names the weekday, so a "payment due in 30 days" landing on a Sunday is visible immediately, before it surprises anyone.
Does it handle month ends sensibly?
Yes — adding days is unambiguous (unlike adding "months"): 30 January + 5 days is 4 February, full stop. That is why contracts count in days, and why this calculator does too.