Date Difference Calculator

Calculating the difference between two dates seems simple but has several nuances depending on what you're measuring — calendar days, working days, or full months. Calendar days: The most straightforward — count every day between the two dates including weekends and holidays. Useful for general time spans, age calculation, and deadlines. Working days: Exclude weekends (Saturday and Sunday). Useful for project planning, contract deadlines, and business contexts. Some calculators also exclude public holidays, though these vary by country. Months and years: Month differences are trickier because months have different lengths. February has 28–29 days while January has 31. A proper month difference calculation accounts for this — the distance from January 31 to February 28 is 1 month, not 28 days. Common uses: How many days until an event, days between two historical dates, age in days, project duration, contract length, deadline calculation, and days until a birthday or anniversary.