Post Judgment Interest Calculator

Calculate the interest owed on a money judgment from the judgment date to the payoff date, using simple interest or annual compounding at your court's rate.

Quick Facts

Simple interest formula
I = P × r × (days / 365)
P is the judgment amount, r is the annual rate as a decimal, days is the time elapsed since judgment.
Annual compounding formula
A = P × (1 + r)^(days / 365)
Interest is added to the balance once per year; a partial final year is compounded fractionally.
Rate source
Set by statute or the judgment
Enter the specific statutory or court-ordered rate for your jurisdiction — it is not a market rate you choose.

Your Results

Calculated
Interest accrued
-
Since the judgment date
Total amount due
-
Judgment plus accrued interest
Days since judgment
-
Judgment date to as-of date
Average daily interest
-
Accrued interest ÷ days elapsed

Ready

Enter the judgment amount, rate, and dates, then press Calculate.

How the Post Judgment Interest Calculator works

Post-judgment interest is the interest that accrues on a money judgment between the date a court enters the judgment and the date it is actually paid. It compensates the winning party for the time value of money while the losing party still owes the debt. The rate and method (simple or compounding) are set by statute or by the judgment itself — this calculator applies whichever rate and method you enter to the exact number of days between your two dates.

The formulas

For a judgment amount P, an annual rate r (as a decimal), and t years elapsed (days elapsed divided by 365), the calculator supports two standard methods:

Simple interest: I = P × r × t

Annual compounding: A = P × (1 + r)t, so I = A − P

Simple interest charges the full rate on the original judgment amount for the whole period, with no interest-on-interest. Annual compounding adds accrued interest to the balance once each year, so later interest is calculated on a larger base; a partial final year is compounded fractionally using the exponent t.

Worked example

Take a $50,000 judgment entered on January 15, 2025, with a 6% annual post-judgment rate, paid off on August 19, 2026 — about 581 days, or roughly 1.592 years. Under simple interest: I = $50,000 × 0.06 × 1.592 ≈ $4,775, for a total of about $54,775. Under annual compounding: A = $50,000 × (1.06)1.592 ≈ $54,859, about $84 more than simple interest because the compounding method earns interest on the first year's accrued interest as well.

Why the rate and method matter

  • The rate is not negotiable: unlike a loan, you don't shop for a post-judgment rate. Federal court judgments accrue interest under 28 U.S.C. Section 1961 at a rate tied to the one-year Treasury bill yield in effect when judgment was entered; most states set their own fixed statutory rate (commonly in the 4%–10% range) or reference a different benchmark. Always confirm the rate that applies to your specific judgment and court.
  • Simple vs. compounding changes the total: the difference is small over short periods but grows for judgments left unpaid for years, since compounding effectively charges interest on unpaid interest.
  • The clock usually starts at entry of judgment, not at the date of the underlying injury or contract breach — that earlier period is typically covered separately by prejudgment interest, a different calculation.

What this calculator does not handle

This tool assumes the full judgment amount remains unpaid for the entire period you enter — it does not automatically account for partial payments. If the debtor paid part of the judgment partway through, calculate interest on the original balance up to the payment date, reduce the principal, and run this calculator again for the remaining balance and remaining period, then add the two interest figures together. It also uses a fixed 365-day year rather than jurisdiction-specific day-count conventions, which is accurate for most purposes but may differ slightly from a court clerk's exact figure in leap years or under a 360-day convention.

Frequently Asked Questions

How is post-judgment interest calculated?
Post-judgment interest is calculated on the judgment amount from the date the judgment is entered until it is paid. With simple interest, Interest = Principal × annual rate × (days / 365). With annual compounding, the balance is multiplied by (1 + rate) raised to the number of elapsed years, including a fractional year for any partial period, and the interest is the increase over the original judgment amount.
What interest rate applies to a judgment?
The rate is set by law or by the judgment itself, not chosen by the parties. Many U.S. states set a fixed statutory rate for civil judgments, while federal court judgments accrue interest under 28 U.S.C. Section 1961 at a rate tied to Treasury bill yields. Enter the specific rate that applies in your court and jurisdiction.
Does post-judgment interest compound or stay simple?
It depends on the jurisdiction. Some states apply simple interest for the life of the judgment, while federal judgments and some states compound interest annually. This calculator supports both methods so you can match the rule that governs your judgment.
What if partial payments were made before the judgment was satisfied?
This calculator assumes the full judgment amount remained unpaid for the entire period between the judgment date and the as-of date. If partial payments were made, most jurisdictions require reducing the principal on the payment date and calculating interest on the remaining balance separately for each period, then summing the results.

Related calculators