Days Between Two Dates
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About this calculator
Enter two dates to find out exactly how many days are between them. The result is always a positive number regardless of date order. This is the most commonly used date difference calculation.
How it works
The calculator normalizes both dates to midnight, computes the absolute difference in milliseconds, and divides by 86,400,000 (the number of milliseconds in one day). By normalizing to midnight, the result is always a clean whole number of days. This avoids timezone and daylight saving time complications that can cause off-by-one errors.
When to use this calculator
Count remaining days until a deadline, vacation, or event. Calculate the length of a trip, rental period, or contract term. Determine how many days are left in a medication course. Track streaks and habits by counting consecutive days. Real estate professionals calculate days-on-market for property listings. Insurance adjusters compute elapsed days for claim processing timelines.