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Everyday Life Calculators

Day of the Year Calculator

Find the day-of-year number (1-366) for any date, plus how many days remain until the year ends.

Day of the year
Days remaining in year
Total days in year
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About the Day of the Year Calculator

Every date can be expressed as a single day number within its year, counting January 1 as day 1 and continuing through December 31 as day 365 (or 366 in a leap year). This numbering is sometimes called an "ordinal date."

Formula: Day of Year = (Date − January 1 of that year) ÷ 1 day + 1

This calculator also checks whether the year is a leap year to correctly report the total number of days it contains, then subtracts the day-of-year number to show how many days remain. Ordinal dates are widely used in programming, manufacturing date codes, agriculture and scheduling systems where a plain day count is more convenient than a month-and-day format.

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