Days Between Dates Calculator - Count Days Between Two Dates
Use this free calculator to find the exact number of days between any two dates. Get total days, weeks and remaining days, business days (excluding weekends), and total hours between your chosen dates.
How to Count Days Between Two Dates
Counting the days between two dates is a common need for project planning, event countdowns, age calculations, and contract durations. While simple in concept, accurate date arithmetic must account for varying month lengths, leap years, and the distinction between calendar days and business days.
Calendar Days vs. Business Days
Calendar days include every day between two dates, including weekends and holidays. Business days, also called working days, count only Monday through Friday and exclude Saturdays and Sundays. For legal and business purposes, the distinction matters significantly. A 30-calendar-day period contains approximately 22 business days. When contracts or deadlines specify "days," always confirm whether they mean calendar days or business days.
Including vs. Excluding the End Date
The "days between" two dates typically excludes both the start and end dates, counting only the days in between. For example, the days between Monday and Wednesday is 1 day (Tuesday). However, some calculations include the end date. Our calculator uses the standard mathematical approach: it counts the difference, meaning from January 1 to January 10 equals 9 days. If you need to include the end date, add 1 to the result.
Accounting for Leap Years
Leap years add complexity to date calculations. A leap year occurs every 4 years and adds February 29 to the calendar, making the year 366 days instead of 365. The rule is: a year is a leap year if it is divisible by 4, except for century years, which must be divisible by 400. So 2000 was a leap year, but 1900 was not. Our calculator handles leap years automatically using JavaScript's built-in Date object.
Business Days Calculation Method
To calculate business days, the calculator determines the total number of days between the two dates and then subtracts the weekend days. For each complete week in the range, there are exactly 2 weekend days (Saturday and Sunday). The remaining partial week days are checked individually. Note that this method does not exclude public holidays, as those vary by country, state, and even employer. For precise business day counts in a professional context, you may need to manually subtract applicable holidays.
Frequently Asked Questions
Does this calculator include the end date?
No, this calculator counts the days between the two dates, meaning the end date is excluded from the count. The result represents the difference between the start and end dates. For example, from January 1 to January 5 equals 4 days (January 2, 3, 4, and the span to January 5). If you need to include the end date in your count, simply add 1 to the result.
How do you calculate business days between two dates?
Business days are calculated by counting only weekdays (Monday through Friday) and excluding weekends (Saturday and Sunday). The calculator determines the total number of complete weeks in the range and multiplies by 5 business days per week, then checks any remaining days individually. This calculation does not account for public holidays, which vary by location. For a precise count, subtract any holidays that fall on weekdays within the range.
How many days are in a year?
A standard year has 365 days. A leap year has 366 days, with the extra day added on February 29. Leap years occur every 4 years, with the exception that century years must be divisible by 400 to be leap years. The next several leap years are 2028, 2032, and 2036. On average, a year is 365.2425 days long, which is why we have leap years to keep the calendar aligned with Earth's orbit around the sun.
How do I count days for a legal deadline?
Legal deadlines can be tricky. Some jurisdictions count calendar days while others count business days. Some include the start date, some exclude it. In many legal contexts, if the deadline falls on a weekend or holiday, it extends to the next business day. Always check the specific rules for your jurisdiction and document type. When in doubt, consult with a legal professional about the applicable counting method.