How to Count the Days Between Two Dates
Learn how the duration between two dates is measured in years, months, and days, how total days and weeks are counted, and how business days differ.
Quick Answer
The date difference is the duration between dates, and this date difference calculator reports the days between two dates along with the same gap in weeks and in years, months, and days. Enter a start date and an end date and it also counts the weekdays in the range. As a days between dates and time between dates tool it is exact: it steps through the calendar and accounts for leap years and each month's real length.
Try The Date Difference Calculator →How the Duration Is Measured
To count the days between two dates, the tool converts each date to a day number and subtracts, so the total-days figure is a plain, exact count. The years-months-days breakdown is built the other way, one unit at a time: subtract the day, then the month, then the year, borrowing the real length of the preceding month whenever the day comes out negative. That is how the duration between two dates is measured without ever assuming a fixed month length. Total weeks is simply the number of complete seven-day weeks inside the total days.
What Business Days Mean in a Date Range
Alongside the calendar totals, this business days calculator reports a weekday count: the number of Monday-to-Friday days in the range. What business days mean in a date range is simply the calendar days with Saturdays and Sundays removed. To find the number of weekdays between two dates, the tool counts whole weeks (five weekdays each) and then checks the leftover days one by one. Public holidays are left in, because they differ by country, so treat the weekday count as working days before local holidays.
Examples
A project span. For example, from 1 January 2026 to 8 July 2026 is 6 months and 7 days, which is 188 days, 26 weeks between dates, and 134 weekdays.
A countdown. For example, entering today as the start and a deadline as the end shows how many days between dates remain, and how many of those are working days.
Reversed dates. For example, if you enter the later date first, the tool still reports the same span and notes that the dates are in reverse order.
Calendar Duration vs Total Days vs Business Days
The three views answer different questions. The calendar duration versus total days choice is about phrasing: "6 months and 7 days" and "188 days" describe the identical gap, which is why total days and the years-months-days breakdown always agree. Total days versus business days is a real difference: total days counts every calendar day, while business days count only weekdays. Use calendar months and weeks for how long something lasts, and the weekday count when you are planning work that skips weekends.