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Day of the Year Calculator
See which numbered day of the year a date is, from 1 on January 1 to 365 or 366 on December 31, along with the days remaining and the percentage of the year gone.
- Days left in the year
- 81
- Days in the year
- 365
- Year completed
- 77.8%
- Ordinal date
- 2026-284
Saved setups
Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.
Your recent calculations
Results you calculate here are kept on this device so you can come back to them.
Formula
How to use it
- Choose a date, or leave it as today.
- Read the day number and days remaining.
Worked examples
October 11, 2026
- Day of the year
- 284
- Days left in the year
- 81
- Days in the year
- 365
- Ordinal date
- 2026-284
February 29, 2024
- Day of the year
- 60
- Days left in the year
- 306
- Days in the year
- 366
Ordinal dates
The year followed by the three-digit day number, such as 2026-284, is an ordinal date in ISO 8601. Manufacturing, logistics and the military use it for date codes and often call it a “Julian date”, although the astronomers’ Julian Day is a different, continuous count.
Questions people ask
What day of the year is it today?
Leave the date as today. October 11 is day 284 in a common year and day 285 in a leap year.
What is the 100th day of the year?
April 10 in a common year and April 9 in a leap year.