Days Between Dates Calculator
Count the exact days between any two dates. Results shown in days, weeks, months, and business days — instantly.
→ / ← to move · ↑↓ to adjust
→ / ← to move · ↑↓ to adjust
How to Use This Calculator
Select a start date and an end date. The result updates instantly in four units: total days, complete weeks, calendar months, and business days (weekdays only). Use the ⇄ button to swap the two dates. If the end date is before the start date, the calculator still shows the correct count — just note the dates are in reverse order.
Calendar Days vs Business Days
Calendar days count every day including weekends and holidays. Business days count only Monday through Friday. The difference matters for project timelines, contract deadlines, and shipping estimates. A 14-calendar-day window starting on a Monday contains 10 business days. A 10-business-day deadline from a Monday falls on a Friday two weeks later.
Note that this calculator does not account for public holidays, which vary by country and region. For precise business day counting that includes holidays, add your regional holiday count to the calendar days result and subtract from the business days result accordingly.
How Months Are Calculated
Calendar months are not equal in length (28, 29, 30, or 31 days), which means "how many months between two dates" doesn't have a clean answer based on days alone. This calculator counts complete calendar months — the number of times the month counter ticks over between the two dates. The remaining days are shown separately. For example, January 15 to April 3 = 2 complete months and 17 days (not 3 months).
Common Use Cases
Project management: How many days until the deadline? How many working days remain in the sprint?
Legal and contracts: Lease agreements, notice periods, and loan terms often specify exact day counts. A "30-day notice" starting October 1 ends October 31.
Travel planning: How long is the trip? How many days until departure?
Health and fitness: How many days into a diet or training program? How long until the event you're training for?
Age verification: Combined with a birth date, days-between gives you an exact age in days — useful for precise eligibility calculations.
Frequently Asked Questions
Does the calculator include or exclude the start and end dates?
The calculator counts the gap between the two dates — the end date is included, the start date is not. January 1 to January 3 = 2 days. If you need both endpoints (e.g., "the event runs from the 1st through the 3rd"), add 1 to the result.
How do I count only weekdays between two dates?
Use the "Business days" figure shown in the results. It counts Monday–Friday and excludes Saturdays and Sundays. Public holidays are not excluded.
How many days is 3 months?
Three calendar months is 89–92 days depending on which months. Jan–Mar = 90 days (91 in a leap year). Apr–Jun = 91 days. Enter the specific dates for a precise count.
How do I calculate weeks between two dates?
The calculator shows complete weeks automatically. Divide total days by 7 — the integer part is complete weeks, the remainder is extra days. 30 days = 4 weeks and 2 days.
Can I calculate dates in the past?
Yes. Enter any two historical dates and the calculator shows the difference. There is no minimum or maximum date range.