Date Calculator
Add or subtract days, weeks, months, or years from any date — or find the exact number of days between two dates, including business days.
Days From Today — Quick Lookup
Days Ago From Today — Quick Lookup
Weeks From Today — Quick Lookup
Months From Today — Quick Lookup
How the Date Calculator Works
Enter any starting date, an amount, and a unit (days, weeks, months, or years). Choose whether to count forward ("from this date") or backward ("before this date"). The calculator returns the exact result date, the day of the week, and the number of business days (Monday–Friday, excluding weekends).
The Date Difference tab works in reverse: enter a start and end date to find the gap in calendar days, weeks, months, years, and business days. All calculations run instantly in your browser — no data is sent anywhere.
All spoke pages are updated daily at midnight US Eastern time.
Days, Weeks, and Months — What's the Difference?
Adding Days
- ·Exact — always a fixed number of calendar days
- ·30 days ≠ 1 month (months have 28–31 days)
- ·Business-day count is always precise
- ·Used in: legal deadlines, billing cycles, shipping windows
Adding Weeks
- ·Always a multiple of 7 — lands on the same weekday
- ·6 weeks = exactly 42 days (no ambiguity)
- ·Each week contains exactly 5 business days + 2 weekend days
- ·Used in: sprint cycles, pregnancy tracking, leave periods
Adding Months
- ·Variable — the day count depends on which months are included
- ·6 months can be 181, 182, or 183 days depending on the year
- ·Same calendar date, different month (e.g., Mar 15 → Sep 15)
- ·Used in: subscriptions, visa validity, employment contracts
Common Date Calculation Use Cases
Legal & Contractual Deadlines
Count exact calendar days for notice periods, filing deadlines, statute of limitations, and contract termination windows. Courts and agencies count days precisely — not months.
Business & Project Planning
Find end dates for sprints, quarters, and milestones. Convert between weeks and days for sprint planning. Calculate how many business days remain in a quarter.
Health & Medical
Track pregnancy weeks, recovery periods, and medication schedules with precision. Medical timelines often count in weeks, not months.
Finance & Subscriptions
Calculate subscription renewal dates, loan terms, and billing cycle end dates. Determine exact expiry dates for warranties, trial periods, and payment terms.
Travel & Visa Planning
Stay within visa duration limits, plan return flights, and track the Schengen 90-in-180-day rule. Date arithmetic prevents overstaying.
HR & Employment
Calculate probationary period end dates, annual review dates, notice periods, and FMLA eligibility windows for accurate HR administration.