Date Calculator
Add or subtract days from a date, or count days between dates.
90 days after
December 1, 2026
Day of week
Tuesday
Deadlines and windows
Contract deadlines, return windows, and medication schedules all reduce to date arithmetic. '90 days from signing' counts calendar days by default — business-day counts differ, and this matters exactly when a deadline lands on a weekend.
Inclusive or exclusive?
'Days between' here excludes the start day and includes the end (June 1 → June 3 = 2 days). Legal and billing contexts sometimes count inclusively — one day more. When a deadline matters, confirm which convention applies.
Frequently asked questions
- How does the Date Calculator work?
- Add or subtract days from a date, or count days between dates.
- Is the Date Calculator free to use?
- Yes. The Date Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
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