It looks like you want to know how many days until the 13th of a certain month, but you didn't specify which month. Assuming you mean the next 13th day from today, May 23, 2025:

• The next 13th day will be June 13, 2025.
• From May 23 to June 13 is 21 days.

So, there are 21 days until June 13, 2025. If you meant a different month or year, please let me know!