Look at the amount on the court document, for what the specific amount of the judgment was.
There are amortization tables on the internet, where you can put in an amount, the amount that is being paid monthly, and the percentage of interest charged.
You will then get a table showing what the total amount owed should be, month on month.
Don't go by the 10%, necessarily. Check with your state for the actual amount that they allow to accrue on judgments.
If you haven't paid anything, of course, 10%/year is easy.
On a $1000 judgment, after a year, it would have grown to $1100, etc.