Day of year calculator

Date

Day of the year —

Counting from 1 January

About that date

Days remaining —

Day of the week —

ISO week —

Quarter —

Leap year —

Note Enter a date

Day number plus days left = 365 or 366

The day of year counts from 1 January as day 1. In a common year 31 December is day 365; in a leap year it is 366. Anything after February shifts by one between the two.

How to find the day of the year

1 Enter the date.

2 Read the day number and the days remaining.

3 They always add to 365 or 366.

4 Leap years shift every date after February by one.

The ordinal date is what ISO 8601 calls this, written as 2026-235, and it turns up in aviation, manufacturing lot codes and older mainframe systems because it sorts and subtracts trivially. It is often loosely called a Julian date, which is a different thing — the true Julian Day Number counts days continuously from 4713 BC and is currently a seven-digit number, not one between 1 and 366.

Questions

What day of the year is it? −

Leave the date at today — the number and the days remaining are both shown.

Is this a Julian date? +

How does a leap year change it? +

What is day 100? +

Where are ordinal dates used? +

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