D-Day Calculator
Calculate day counts, anniversaries, 100 days, and more—all in one place.
Enter Base Date
Selected Date ~ Today (June 22, 2026)
D-Day Calculator Guide
A convenient tool for all your date-related calculations in one place. It supports counting days from a specific date to today, calculating the difference between two dates, adding or subtracting days, and computing anniversaries like 100, 200, and 1000 days.
Perfect for couple anniversaries, counting how many days since birth, project deadlines, and more.
FAQ
Does the 100-day calculation include the start date?
Yes, this calculator counts the start date as Day 1. For example, if the start date is January 1, then January 1 is Day 1 and April 10 is Day 100.
How are leap years handled?
All date calculations, including leap years (February 29), are handled automatically and accurately. No additional settings are needed.