Day of Year Calculator
Find the day-of-year number (1–366) for any date, and how many days remain in that year.
Result
What is Day of Year Calculator?
The Day of Year Calculator calculates the sequential ordinal day number (1 through 365 or 366) for any date in the Gregorian calendar. It also reports the total days in that year and how many days remain until the end of the year.
How to use Day of Year Calculator
- 1Choose or input any date using the date picker.
- 2Instantly view the day of the year (1–365 or 366), total days in that year, and the count of days remaining.
- 3Use the ordinal day number for Julian day conversions, tracking project progress, or annual milestones.
Key features
Ordinal Day Calculation
Accurately determines the 1-based day count from January 1 for any Gregorian date.
Days Remaining Metric
Shows the remaining days left in the year toward December 31.
DST-Immune Computation
Uses pure UTC calendar math to avoid daylight saving time hour shifts or rounding errors.
Automatic Leap Year Detection
Accounts for 366 days in leap years and 365 days in common years.
Examples & use cases
Common Year Mid-Year Date
October 15, 2025 in a standard common year
2025-10-15
Day 288 of 365 (77 days remaining)
Leap Year Date
March 1, 2024 following leap day
2024-03-01
Day 61 of 366 (305 days remaining)
Frequently asked questions
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