Small Claims Judgment Interest Calculator
Pre- and post-judgment interest on a small-claims court judgment, at your state's statutory rate.
🔒 Runs entirely in your browser — nothing here is ever uploaded
About the Small Claims Judgment Interest Calculator
Calculates simple pre-judgment and post-judgment interest accruing on a small-claims court judgment, from the underlying claim date through today. It doesn't calculate any entitlement amount — only the interest accruing on a judgment amount you already have.
- Enter the judgment principal amount and any costs/fees the court awarded.
- Enter a pre-judgment interest rate and the number of days from when the claim arose to when judgment was entered (enter 0 if none applies).
- Enter a post-judgment interest rate and the number of days since judgment was entered.
- Read the total amount owed today, with a pre-/post-judgment breakdown.
A $5,000 judgment with $100 in awarded costs, 10%/year pre-judgment interest over 180 days ($246.58), then 10%/year post-judgment interest over 90 days on the $5,346.58 judgment total ($131.83), comes to $5,478.41 owed today.
| Jurisdiction | Annual rate |
|---|---|
| California | 10% |
| New York | 9% |
| Massachusetts | 12% |
| Federal courts | 1-yr Treasury rate (often under 5%) |
Statutory judgment interest rates vary enormously by state — examples include New York at 9%/year, California at 10%/year on most money judgments, Massachusetts at 12%/year, and federal courts using the weekly 1-year Treasury rate (often under 5%). Both rate fields are fully editable — verify your own state's actual statutory rate and accrual rules before relying on this number.
- • Many states don't award pre-judgment interest at all for small-claims cases — set pre-judgment days to 0 if yours doesn't.
- • Confirm whether your state compounds judgment interest or applies simple interest — this calculator only models simple interest, the more common approach.
- • Some states also add interest on court costs awarded as part of the judgment, not just the principal.
- U.S. Courts — Post Judgment Interest Rate (28 U.S.C. §1961) — accessed 2026-08-31
- Steptoe — Pre- and Post-Judgment Interest Rates: Depends on the State — accessed 2026-08-31
Illustrative estimate only, not financial or tax advice. Verify figures with a licensed adviser or your local tax authority.