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D-Day Calculator

Calculate how many days are left until your target date.

What is a D-Day Calculator?

A D-Day calculator lets you see exactly how many days remain until any important date. Add exams, weddings, trips, anniversaries, or deadlines and watch the countdown in real time. You can manage multiple events at once.

Dates in the future show as D-minus (D-7, D-30, etc.). Today's date shows as D-Day!. Past dates show as D-plus (D+1, D+365, etc.). Enable the yearly repeat option for birthdays and anniversaries so the counter automatically resets each year.

D-Day Widget — Embed on Any Website

Click the 'Embed' button on any D-Day card to get an iframe code or a Notion embed URL in seconds. Choose between Simple and Flip styles, then customize font, color, size, shadow, and border to match your site before copying the code.

Works on any platform that supports HTML iframes: WordPress, Wix, Squarespace, Webflow, Ghost, Framer, Shopify, GitHub Pages, and more. For Notion, copy the dedicated embed URL and paste it into an '/embed' block to display the live countdown directly in your page.

How people use it

Exam countdown

Track days until a big test, certification exam, or college entrance exam so you can plan your study schedule.

Wedding & anniversary

Never miss a wedding date or anniversary again — set a yearly repeat and always know how many days are left.

Travel countdown

Count down to your departure date and use the time to prepare packing lists, visas, and itineraries.

Project deadline

Keep work deadlines and assignment due dates front of mind so nothing sneaks up on you.

Frequently asked questions

How is a D-Day calculated?
The target date minus today's date. If the target is in the future it shows as D-N; if it's today it shows as D-Day!; if it has passed it shows as D+N.
What does D+1 mean?
It means the target date was yesterday — one day has passed since the event.
Can I track recurring dates like birthdays?
Yes. Enable the 'Repeat every year' toggle and the calculator will automatically roll over to next year's date once the current one passes.
Are my D-Days saved?
Yes, they are saved in your browser's localStorage. They will still be there after refreshing or closing the tab, but are not shared across devices or browsers.
How many D-Days can I add?
Up to 10 at a time. Manage exams, trips, and anniversaries all in one place.
What happens when the target date is today?
The counter shows 'D-Day!' in bold to mark the occasion.
How do I add a D-Day widget to my blog or website?
Click the 'Get widget' button at the bottom of any D-Day card. Choose a style (Minimal, Dark, Gradient, or Banner) and adjust the size, then copy the iframe code and paste it into any platform that supports HTML embeds — such as WordPress, Notion, Wix, Squarespace, or Webflow.
Which platforms support the D-Day widget?
Any platform that allows HTML iframe embeds, including WordPress, Notion, Wix, Squarespace, Webflow, Ghost, Framer, Shopify, and GitHub Pages. Platforms that block external iframes are not supported.

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