D-day calculator

Target dateBase date (default: today)

Count the start date as day 1

Result

Pick a target date.

The dates you enter stay in this browser and are not uploaded.

Dates you enter never leave this device.

How to use it

1
Pick the target date
Choose the date you are counting toward or from, such as an exam, a trip, or an anniversary. It is read in this browser tab only.
2
Check the base date
The base date starts as today on your device. Change it to count from another day, for example to plan ahead.
3
Read the result
The result shows D-N when the target is ahead, D-Day when it is the same day, and D+N when it has passed.
4
Count the start day as day 1
Turn on the option to count the start date as day 1, the way couples and anniversaries are often counted in Korea.

Common use cases

Exams and deadlines

See how many days are left before a test, a submission, or a project deadline and plan your time.

Anniversaries

Count how many days have passed since a date, with the first day counted as day 1 if you prefer, such as the 100th day.

Trips and events

Follow the countdown to a flight, a wedding, or a launch day without keeping a separate calendar.

Security and privacy

Your dates stay on your device

The days are counted by browser code on your device while you type. No upload route exists for this tool, no request carries your dates, and nothing is saved after you close the tab. You can enter private dates without sending them to anyone.

Supported inputs and outputs

What it uses

A target date: year, month, and day
A base date, set to today on your device by default
An option to count the start date as day 1
Whole days only, so the time of day never shifts the result

FAQ

Are my dates uploaded?

No. The counting runs inside your browser. No request that carries your dates is sent to Frisbly or anyone else.

What do D-N and D+N mean?

D-N means N days are left until the target date. D-Day is the target day itself. D+N means N days have passed since it.

What does counting the start day as day 1 do?

For a date in the past, the target day is counted as day 1, so the result is one more than the plain count. For a future date nothing changes.

Which time zone is used?

Dates are whole calendar days. The base date follows the clock of your device, and leap years are handled, so the answer does not drift by a day.

Is there a date limit?

Dates from year 1 to year 9999 are accepted. The calendar used is the standard Gregorian calendar.