Date Calculator: Find Days Between Dates or Add Days to a Date
A date calculator is an essential tool for anyone who needs to count the number of days between two dates or determine a future or past date by adding or subtracting days. While this sounds simple, manual calculations can be tricky due to months of varying length, leap years, and the difficulty of counting across year boundaries.
Our date calculator offers two modes. The first mode calculates the exact number of days between any two dates, also showing the equivalent in weeks and approximate months. This is useful for project planning, tracking pregnancy weeks, calculating contract durations, or figuring out how many days until a deadline.
The second mode lets you add or subtract a specific number of days from any starting date. Enter a negative number to go backward in time. This is perfect for computing due dates, warranty expiration, notice periods, or any scenario where you need to know "what date is X days from now?"
All results are computed instantly using your browser's built-in date handling, which correctly accounts for daylight saving time transitions, leap years, and month boundaries. The result date is displayed both in a localized long format (with day of the week) and in ISO format for easy reference.