Date Difference Calculator

Years, months, weeks, days, hours, minutes, and seconds - both as total counts and broken down into largest units. Every calculation is instant and updates as you change dates.

Yes. The calculator uses JavaScript's native Date object, which correctly handles leap years, daylight saving transitions, and all calendar edge cases.

All calculations use local time as displayed. If you need UTC-based differences, ensure both dates are in the same timezone or convert to UTC before comparing. The calculator shows the raw difference between the two date values, not accounting for timezone offsets between dates entered in different zones.

JavaScript's Date object supports dates from approximately -271,821 BCE to 275,760 CE. For practical use, the calculator handles any dates within ±100,000,000 days from 1970, far beyond any real-world need. Very large differences are shown in total days to avoid imprecise year/month breakdowns.

This calculator shows calendar days (including weekends and holidays). For business days, subtract roughly 2 days per 7 (for weekends) or use a dedicated business day calculator that accounts for holidays. The total count shown can be manually adjusted for rough business day estimates.

Yes, click the Swap button to instantly reverse the start and end dates. The Now button sets the end date to the current time.