Post Judgment Interest Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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A finance number becomes easier to trust when you can trace it back to the inputs. Post Judgment Interest Calculator estimates interest accrued on a judgment between the entered judgment date and payment date using the entered annual post-judgment interest rate.

What this calculator does

Post Judgment Interest Calculator estimates interest accrued on a judgment between the entered judgment date and payment date using the entered annual post-judgment interest rate. The form asks for judgment amount, post-judgment annual interest rate, judgment date and payment date. The result should therefore be read as a calculation from those displayed assumptions, not as live market, lender, tax, or government-program data unless the page explicitly supplies such a feed.

How to use it

Enter Judgment amount, Post-judgment annual interest rate, Judgment date and Payment date. Keep monetary inputs in one currency; the currency selector formats results and does not convert exchange rates. Enter rates and percentages on the scale shown by the field label; do not silently switch between a decimal and a percent. Before calculating, recheck Judgment amount, Post-judgment annual interest rate, Judgment date against the source values you intend to model. If a default value is already filled in, confirm that it matches the scenario you actually want to test rather than assuming the preset is current or personally appropriate.

How the calculation works

Days accrued = payment date − judgment date. Estimated interest = judgment amount × annual interest rate × days/365. Total due is judgment amount plus that simple-interest estimate. This is the calculation method to use when checking the result from Post Judgment Interest Calculator; values not represented by a visible input should not be inferred as part of the model.

Example

A $10,000 judgment at an entered 5% annual rate over 364 days produces about $498.63 of simple interest using days/365. Federal or state law may require a different rate or compounding method.

How to interpret the result

A later payment date or higher entered rate increases the estimated accrued interest. The result is only as accurate as the legally applicable rate and compounding method entered. The result is most informative when you also look at the component values that drove it.

Limitations and notes

Post-judgment interest rules are jurisdiction-specific. For many U.S. federal judgments, 28 U.S.C. §1961 uses a Treasury-linked rate, daily computation, and annual compounding; this calculator uses simple days/365 interest, so it may not match a federal-court calculation. Recalculate when rates, balances, prices, dates, or policy rules change.