This date calculator does the three date jobs people need most: count the days (and weeks and business days) between two dates, and add or subtract days from a date to find the new date. Deadlines, due dates, project timelines and 90-day notices — all answered instantly.
Days Between Two Dates
Add or Subtract Days
What Is a Date Calculator?
A date calculator performs arithmetic on calendar dates: how many days separate two dates, how many of those are business days, and what date falls exactly N days from a given date. Counting on your fingers fails across month boundaries and leap years; this tool handles both automatically. It is part of our Everyday Life Calculators collection.
Examples (Verified)
- January 1, 2026 → December 31, 2026: 364 days (52 weeks exactly), of which 260 are business days and 104 are weekend days
- October 21, 2026 + 90 days = January 19, 2027 — the classic 90-day deadline
- Deadline math: "30 days from March 15" = April 14 — the add-days mode never miscounts a 31-day month
Common Uses
- Contracts and notices: 30/60/90-day terms, cancellation windows, probation periods.
- Project planning: business days between kickoff and launch, excluding weekends.
- Legal and HR: response deadlines, leave balances, tenure milestones.
- Health and life events: counting down to a due date or appointment (for age itself, use the Age Calculator).
Need just a quick days-only count? Our Days Calculator does that single job; the Weeks Between Calculator focuses on week counts, and the Chronological Age Calculator handles exact ages for forms and records.
Counting Rules Worth Knowing
- Exclusive vs. inclusive: "days between" here counts the end date but not the start date — the standard difference. For an inclusive count (both endpoints), add 1.
- Business days are Monday–Friday and do not exclude public holidays, which vary by country and state — adjust manually for your calendar.
- Leap years add February 29; any span crossing it includes the extra day automatically.
Related Tools
- Age Calculator — exact age from a birth date
- Days Calculator — simple days-between count
- Weeks Between Calculator
- Chronological Age Calculator
Frequently Asked Questions
How many days are in 2026?
365 — 2026 is not a leap year. From January 1 to December 31 is a difference of 364 days.
How do I calculate 90 days from today?
Put today's date in the add-days box, enter 90, and the tool returns the exact date — for example, October 21, 2026 + 90 days = January 19, 2027.
What are business days?
Monday through Friday, excluding weekends. Public holidays are not deducted because they differ by location.
Does this calculator handle leap years?
Yes — February 29 is counted automatically in any span that includes it.
What is the difference between this and the Days Calculator?
The Days Calculator counts days only. This Date Calculator additionally counts business and weekend days, breaks the span into weeks, and adds/subtracts days to find a date.
Is this date calculator free?
Yes — free, instant, no sign-up.