Day of the Year Calculator
Find out what day number a date is in the year. Also calculate the percentage of the year that has passed.
Date Information
Information
- Day of the week:Sunday
- Day of the year:277
- Week of the year:41
Day of the year calculator
Formula
Count the ordinal day number within the year (1-365 or 1-366 for leap years).
Add 1 if past February in a leap year.
Worked example
What day of the year is 15 August?
- January: 31 days
- February: 28 days (29 in leap years)
- March: 31 days
- April: 30 days
- May: 31 days
- June: 30 days
- July: 31 days
- August 15: 15 days
Total: 31 + 28 + 31 + 30 + 31 + 30 + 31 + 15 = 227
So 15 August is day 227 of the year (228 in leap years).
How to use
- Enter the date
- Click "Calculate" to see the day number
Day number table
| Month | Day | Day of Year | |-------|-----|-------------| | Jan 1 | 1 | 1 | | Feb 1 | 32 | 32 | | Mar 1 | 60 | 60 (61 in leap years) | | Apr 1 | 91 | 91 | | May 1 | 121 | 121 | | Jun 1 | 152 | 152 | | Jul 1 | 182 | 182 | | Aug 1 | 213 | 213 | | Sep 1 | 244 | 244 | | Oct 1 | 274 | 274 | | Nov 1 | 305 | 305 | | Dec 1 | 335 | 335 | | Dec 31 | 365 | 365 (366 in leap years) |
Remaining days
To calculate remaining days in the year:
For 15 August (day 227), remaining = 365 - 227 = 138 days.
Common use cases
- Tracking year progress
- Project planning with year-end deadlines
- Financial year calculations
- Academic year tracking
- Personal goals and resolutions
FAQ
What is day 100? April 10 (or April 9 in leap years).
What is day 200? July 19 (or July 18 in leap years).
What is day 365? December 31 in non-leap years.
Is there a day 0? No, days are numbered 1-365 (or 1-366).
How do I calculate a date from day number? Subtract month by month until you find the right range.