Date Difference Calculator
Calculate the difference between two dates in years, months, weeks, and days, with optional inclusive counting and a business-days-only count that excludes weekends.
Enter a start date and an end date to calculate the difference between them in years, months, weeks, and days, with optional inclusive counting and business-day counting.
Understanding Date Differences
This calculator finds the difference between two dates using the same calendar-based method as counting age by hand: it counts complete years, then complete months, then remaining days between the start date and the end date. This correctly accounts for months of different lengths and leap years, rather than simply dividing the total number of days by 365.25. Below the headline result, the same span is also shown as total months, weeks, days, hours, minutes, and seconds.
By default, this calculator counts the days from the start date up to but not including the end date — the same convention used when subtracting one date from another (an 'exclusive' count). Checking 'Include end day' adds one extra day, counting both the start date and the end date themselves as part of the span (an 'inclusive' count). This matters most for short spans: from a Monday to the following Friday is 4 days exclusive, but 5 days inclusive if you're counting how many calendar days the span touches, such as for a rental period or a multi-day event.
Calculating the exact span between two dates comes up constantly in everyday planning: figuring out how many days remain until a deadline or event, calculating the length of a relationship or employment period, determining the length of a rental, loan, or billing period, and working out how many days have passed since a specific milestone.
By default, all totals on this page count every calendar day, including weekends. Checking 'Count business days only' adds a Business Days figure that counts only Monday through Friday within the span (using the same inclusive or exclusive range you've already selected) — useful for estimating working time for deadlines, contracts, or shipping estimates. This calculator only excludes weekends; it doesn't know about public holidays, since those vary by country, region, and industry.
Frequently Asked Questions
About this calculator
This calculator finds the difference between a start date and an end date, broken down into years, months, and days using calendar-accurate math, along with the same span expressed as total months, weeks, days, hours, minutes, and seconds. An 'include end day' option lets you switch between exclusive counting (the default, matching simple date subtraction) and inclusive counting (adding one day to count both endpoints), and a separate option adds a business-days-only count that excludes Saturdays and Sundays.
- Calendar-accurate breakdown — The difference is calculated as complete years, months, and days using real calendar math, correctly handling varying month lengths and leap years.
- Inclusive or exclusive counting — Choose whether the end date itself counts as part of the span — useful for rental periods, multi-day events, or billing cycles where both endpoints should be counted.
- Business days only — Optionally count only Monday-through-Friday business days within the span, excluding weekends — useful for estimating working time for deadlines, contracts, or shipping estimates.
- Multiple total units — See the same span expressed as total months, weeks, days, hours, minutes, and seconds, not just a single years/months/days breakdown.
- Day of the week for both dates — Instantly see which day of the week the start date and end date fall on.
- Handles any date range — Works across any span, from a few days to many decades, with leap years accounted for automatically.