Calculating Interest on Debt

My question involves collection proceedings in the State of: NY (NYC)

We are the landlord/judgment creditor. We sued a former tenant for unpaid rent in small claims and won a default judgment.

The tenants debt started to accumulate on, let's say, 1/1/16.

The tenant moved out on, let's say, 5/1/16.

The judgment was dated, let's say, 3/10/18.

The judgment was for the principal amount of $2,500 plus $30 in disbursements for a total of $2,530. No interest included.

Former tenant now wants to pay the debt. I have two questions concerning interest calculations.

1. To calculate interest owed, do I go back to to 1/1/16 when the debt started, the 5/1/16 move out date or the date the judgment was issued on 3/10/18?

Civil court includes the interest in its judgments back to the date the debt started based on plaintiffs documents. Small claims, for some reason, does not.

2. When calculating interest, am I basing it on principal amount of $2,500 or the principal plus disbursements (total judgment amount) of $2,530?

Thank you.

Calculating Interest on Debt