The simplest method to determine how many days until Christmas is to add up the number of days left between the current date and December 25. Determining the number of days until Christmas becomes more complicated the earlier in the year it is.
- Look up the current date and count to the nearest 25th
Begin by knowing the current date. Count how many days are between that date and the next 25th of a month. For example, if today is Sept. 19, there are 6 days to Sept. 25.
- Determine how many days are in the months between the next 25th and Christmas
If the closest 25th is Sept. 25, there are three months until Christmas, but those three months equal 91 days, because September and November each have thirty days.
- Add together the days
Add the number of days between the current date and the next 25th of the month to the number of days in the months leading to Christmas. For example, the days until Christmas from Sept. 19 is 97.