Day of Year
Calculate the day of the year for any date, so you can track progress and keep a clear overview of the year. Runs locally in your browser, GDPR-compliant.
Your inputs are processed in your browser and are not transmitted to our servers. Note: third-party resources (e.g. advertising and analytics from Google/Cloudflare) and an optional PayPal donation link may transfer data when loading or when clicked. Browser extensions or plugins may be able to read content that is visible in the input fields.
The result will appear here …
How to use this tool (video)
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Day of Year
The day of the year shows you which day number of the calendar year a specific date falls on. Whether you want to track your progress through the year or simply know where you stand in the yearly pace, this tool gives you the answer.
How it works
The calculation sums the days of all preceding months and adds the day number of the current month. Leap years are accounted for: in a leap year February has 29 days instead of the usual 28, which shifts the 60th day of the year. For a concrete example: March 15, 2024 is in a leap year. The sum is 31 days in January plus 29 days in February plus 15 days in March, giving 75. So March 15, 2024 is the 75th day of the year. In 2023, a non-leap year, March 15 would be the 74th day because February had only 28 days.
What the tool can and cannot do
The day-of-year calculator shows the day number for any valid date. It correctly accounts for leap years and returns a day number from 1 to 365 or 366. The tool cannot convert time zones and treats all dates as local dates. It does not calculate remaining days until year end and does not display season or quarter information. It is a pure day-number utility.
Why local processing in the browser
All calculations happen directly in your browser. Your date inputs are never sent to a server. There is no upload, no server log files, and no access by third parties. You need no account and no registration. After the page loads, the calculator works offline too because all resources are cached locally. There is no server that could be attacked and your data is not transmitted over the network. You can try different dates as often as you like and discard results because nothing is stored or tracked.
Frequently asked questions
What is the day of the year?
The day of the year is the running number of a date within a calendar year. January 1 is day 1 and December 31 is day 365 or 366 in a leap year.
Do I need to be online?
No, after the page has loaded once, the calculator works offline. The required resources are cached in the browser and a flaky connection will not interrupt you.
Are my data uploaded?
No, your date inputs are never sent to a server. Everything is processed locally in your browser with no upload and no third party access.
How are leap years accounted for?
The tool automatically detects leap years and adds an extra day in February. This means March 1 is the 61st day in a leap year instead of the 60th day as in a normal year.
Can I calculate the day of the year for any month?
Yes, the tool works for all date entries within a year. Whether January or December, you always get the correct day number.
Is the tool free to use?
Yes, the day-of-year calculator is a free tool that runs directly in your browser. There are no hidden costs or limitations.