How many days until your exam, anniversary, or deadline? Countdowns, business-day counts, and 10 saved D-days in one page.

OgleOgle D-day Calculator is a free countdown tool that tells you exactly how many days remain until your exam, military discharge, wedding anniversary, or project deadline — all in one page. Pick a target date and you instantly get the D-day count, the day of the week, the gap in weeks and days, and the number of business days (excluding weekends). Replace your paper planner with a single browser tab that manages every countdown that matters.

When should you use it? For students counting down to college entrance exams or certification tests, soldiers tracking their military discharge date, couples celebrating their 100-day or 1-year anniversary, employees planning vacation use, PMs and designers watching project deadlines, and parents counting down to their kids' birthdays or school entry ceremonies — anywhere you want to answer the question "how many days until this date?"

Key features. (1) Pick one target date and instantly see D-day, weekday, total days, and business days. (2) Toggle between counting methods that include today (D-day = 0) or exclude it (D-day = 1). (3) Date-interval mode to measure the gap between any two arbitrary dates (e.g. how many days from 2026-01-01 to 2026-12-31). (4) Save up to 10 of your most-watched D-days as cards for at-a-glance comparison. (5) Auto-saved in your browser so your list survives across sessions.

FAQ. Q. How are business days calculated? A. Weekdays only — Saturdays and Sundays are excluded. Q. How many D-days can I save? A. Up to 10. Adding an 11th replaces the oldest one. Q. Can I count past dates too? A. Yes — "plus D-days" such as "days since we started dating" or "days since birth" are fully supported.