Find Day of Year - Calculate What Day of Year a Date Falls On

Our free online find day of year tool calculates what day of the year (1-365/366) any date falls on. Whether you need to know the ordinal day for tracking, planning, or analysis, this tool provides instant calculation with multiple output formats and comprehensive date information.

How to Use the Find Day of Year Tool

Enter Date: Input date in ISO (2024-01-15), US (01/15/2024), EU (15/01/2024), or Full format
Choose Output Format: Select from Number, Ordinal, Percentage, Fraction, or All Formats
Include Additional Info: Optionally include extra date information like percentage of year, days remaining, etc.
Get Result: View the day of year with comprehensive date analysis

Output Formats Explained

Number: Simple number (1-365/366)
Ordinal: Ordinal format (1st, 2nd, 3rd, etc.)
Percentage: Percentage of year completed
Fraction: Decimal fraction of year (0.000000-0.999999)
All Formats: Combination of all formats

Additional Information Provided

Year: The year of the date
Month: Full month name
Day: Day of the month
Day of Year: Which day of the year (1-365/366)
Is Leap Year: Whether the year is a leap year
Days Remaining: How many days left in the year
Percentage Completed: What percentage of the year has passed
Percentage Remaining: What percentage of the year is left
Quarter: Which quarter of the year (Q1-Q4)
Week of Year: Which week of the year

Use Cases for Finding Day of Year

Project Tracking: Track progress through the year
Scientific Research: Astronomical and meteorological calculations
Business Planning: Quarterly and annual planning
Academic Projects: Date analysis and research
Personal Use: Track personal milestones and goals
Programming: Date calculations and algorithms
Data Analysis: Time series and temporal analysis

Leap Year Handling

The tool automatically detects leap years and adjusts the total number of days accordingly:

Common Years: 365 days (February has 28 days)
Leap Years: 366 days (February has 29 days)
Leap Year Rules: Divisible by 4, except century years unless divisible by 400

Date Format Support

ISO Format: 2024-01-15 (YYYY-MM-DD)
US Format: 01/15/2024 (MM/DD/YYYY)
EU Format: 15/01/2024 (DD/MM/YYYY)
Full Format: January 15, 2024

Frequently Asked Questions

How is day of year calculated?

Day of year is calculated by counting the number of days from January 1st to the given date. January 1st is day 1, January 2nd is day 2, and so on. The calculation accounts for leap years, where February 29th adds an extra day.

What's the difference between day of year and day of month?

Day of year is the sequential day number from 1 to 365/366 within the entire year. Day of month is the day number within a specific month (1-31). For example, March 1st is day 1 of March but day 60 or 61 of the year (depending on leap year).

How does the tool handle leap years?

The tool automatically detects leap years using the standard rules: divisible by 4, except century years unless also divisible by 400. Leap years have 366 days, so the day of year can range from 1 to 366 instead of 1 to 365.

What is the percentage format useful for?

The percentage format shows what portion of the year has passed. For example, day 91 (April 1st in a common year) represents 25% of the year completed. This is useful for progress tracking, goal setting, and time-based analysis.

Can I use this tool for scientific calculations?

Yes, day of year is commonly used in astronomy, meteorology, and other scientific fields. It provides a simple way to reference dates without the complexity of different month lengths, making it ideal for calculations and data analysis.

What additional information is most useful?

The most useful additional information depends on your needs: percentage completed for progress tracking, days remaining for planning, quarter for business analysis, and week of year for scheduling. The tool provides all of these to give you comprehensive date analysis.