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Date & time

Day of Year Calculator

Find a calendar date’s ordinal day number and the days remaining in its year.

Date conventions explained belowClear start and end values

Set your dates & time

Runs on your device

TIME SUMMARY

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter calendar date.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Count calendar days from January 1 and add one. Days remaining exclude the selected date and end on December 31.

A WORKED EXAMPLE

March 1, 2024 is day 61 because 2024 contains February 29. There are 305 days remaining after that date.

What to keep in mind

Uses the Gregorian calendar and UTC calendar arithmetic. This ordinal day number is not an astronomical Julian Date.

Common questions

Does January 1 count as day zero?

No. January 1 is day 1 and December 31 is day 365 or 366.

Does daylight saving time change the result?

No. Calendar dates are processed without local clock changes.

Methodology maintained by ClarityKit. How these tools are built and checked.