Date Calculator
Find how many days, weeks, months and business days lie between two dates — useful for deadlines, contracts, notice periods and planning.
Enter your details above — results update as you type.
Formula and calculation
Worked example
From January 1, 2026 to October 16, 2026 is 288 days — that is 41 weeks 1 day, or 9 months 15 days on the calendar. 206 of those days are business days.
Which convention should you use?
Courts, contracts and payroll systems disagree on whether “seven days” includes the starting day — it is worth knowing the convention you are dealing with. Rent and billing periods usually run from a start date to the day before the next one; many legal notice periods count from the day after delivery. When in doubt, count the ways that matter: this calculator shows both the plain difference and the count including the end day, and the business-day figure is handy for anything that only progresses on working days.
What the results mean
- Days between
- The number of days between the two dates — counting business days only when that option is on. By default the start day is not counted and the end day is; the “include the end day” option shifts both.
- In weeks
- The same span in whole weeks plus leftover days.
- In calendar terms
- The span in calendar terms — whole years, months and days — how most people describe a deadline (“three months and a day”).
- Business days
- Weekdays (Monday–Friday) within the span. Public holidays are not subtracted — for contract deadlines, check the holiday calendar too.
Frequently asked questions
How many days are between two dates?
Count the calendar days from one date to the other, letting leap years fall where they do. For example, January 1 to October 16 is 288 days — this calculator does the counting for any pair of dates, plus weeks, months and business days.
Is the start day or end day counted?
By default this calculator counts the end day but not the start day, which matches the typical “days between” answer. If your deadline counts both — “delivered Monday, due Friday, 5 days” — turn on the include-end-day option and the number increases by one.
How are business days different from regular days?
Business days exclude Saturdays and Sundays, so a “10 business day” deadline spans about two calendar weeks. Public holidays are not deducted — a deadline that crosses Christmas week can slip further in practice, so check the holidays that apply to you.
How do I count days from today?
Set the start date to today and the end date to your deadline. The page already starts at today, so usually you only change one of the two dates.