Federal Post Judgment Interest Calculator
Estimate post judgment interest under 28 U.S.C. § 1961 using a fixed annual Treasury based rate, daily accrual, and annual compounding through the payment date.
Enter the unpaid federal judgment principal.
Use the weekly average 1 year constant maturity Treasury yield for the week before judgment.
Enter your judgment amount, rate, and dates, then click Calculate Interest.
Expert Guide to the Federal Post Judgment Interest Calculator
Federal post judgment interest is one of the most important, and often overlooked, economic consequences of a money judgment entered in federal court. Once judgment is entered, the prevailing party may be entitled to additional interest until the judgment is fully paid. That extra amount can become significant when the balance is large, when payment is delayed, or when enforcement activity takes months or years. A reliable federal post judgment interest calculator helps attorneys, creditors, finance teams, insurers, and judgment debtors estimate exposure and plan for payoff.
This calculator is built around the standard federal framework under 28 U.S.C. § 1961. In general, the applicable rate is tied to the weekly average 1 year constant maturity Treasury yield for the calendar week preceding the date of judgment. The rate is fixed as of judgment, interest is computed daily, and it is compounded annually. That structure is very different from many state law systems, where rates may be statutory, contractual, or tied to a different benchmark.
What federal post judgment interest means
Post judgment interest is designed to compensate the prevailing party for the time value of money after the court has entered judgment but before the losing party pays. Put simply, if a defendant owes a judgment today and does not pay until later, federal law generally requires interest to accrue on the unpaid amount for that delay. This encourages prompt payment and helps prevent a debtor from benefiting from the time gap between judgment and collection.
In federal court, the governing statute is usually straightforward, but real world application can still raise practical questions. You may need to determine the right Treasury rate, decide the exact start and end date for the accrual period, handle annual compounding on long running judgments, and confirm whether any partial payments, costs, fees, or amended judgments affect the balance. A good calculator gives you a fast estimate, while a lawyer or financial professional can refine the number for litigation, settlement, or execution purposes.
How this calculator works
This page uses a common federal interest model:
- The annual rate remains fixed based on the Treasury yield in effect for the week preceding judgment.
- Interest accrues daily from the judgment date to the payment date.
- Interest compounds annually, meaning accrued interest is added to principal on each anniversary of the judgment.
- The final partial year is prorated based on the actual number of days elapsed.
The formula can be summarized in plain English as daily simple accrual within each year, followed by annual compounding if the judgment remains unpaid past an anniversary date. If your matter includes partial payments, appellate activity, a supersedeas bond, or a dispute over the judgment base, you should treat the calculator as an estimate rather than a final legal amount.
Inputs you need before calculating
- Judgment amount: Start with the unpaid principal on which post judgment interest runs. Depending on the case, this may include damages and certain taxable costs, but not every component of a case is always treated the same way.
- Annual interest rate: Use the Treasury based rate tied to the week before judgment. This is usually expressed as a percentage, such as 4.75%.
- Judgment date: This is the date from which post judgment interest begins to run, subject to the governing order and procedural posture.
- Payment date: This is the anticipated or actual payoff date.
Those four data points are enough for a useful estimate. If you need a full payoff statement for litigation or settlement, you may also need to consider credits, partial satisfactions, amended judgments, post judgment costs, and whether interest continues on attorneys’ fees awarded after the original judgment.
Example of the federal calculation process
Assume a federal court enters a money judgment for $250,000. The applicable Treasury based rate for the week preceding judgment is 5.00%. If the debtor pays after exactly one year, the simple annual interest would be $12,500, for a total of $262,500. If payment does not occur until two years later, annual compounding matters. After the first anniversary, the balance becomes $262,500. During the second year, interest accrues on that larger amount. The second year interest would then be $13,125, creating a balance of $275,625 before any further accrual.
That is why long running federal judgments can grow meaningfully over time even when the stated rate looks modest. On large judgments, a difference of even one percentage point can translate into thousands or tens of thousands of dollars over the life of the case.
Comparison table: annual interest on a $100,000 federal judgment
The table below shows the effect of different fixed annual rates on a $100,000 balance over one full year before any compounding beyond year one. These are mathematical examples based on actual arithmetic and are useful for quick budgeting and settlement planning.
| Annual Rate | One Year Interest | End of Year Balance | Practical Takeaway |
|---|---|---|---|
| 0.50% | $500.00 | $100,500.00 | Low rate periods reduce exposure, but delay still has a cost. |
| 2.00% | $2,000.00 | $102,000.00 | Moderate rates begin to matter on six figure judgments. |
| 4.50% | $4,500.00 | $104,500.00 | Common modern Treasury ranges can materially affect negotiations. |
| 6.00% | $6,000.00 | $106,000.00 | Higher rate environments meaningfully increase payoff pressure. |
Comparison table: effect of annual compounding on a $250,000 judgment at 5.00%
Federal post judgment interest is computed daily and compounded annually. The compounding feature becomes especially important when collection drags on.
| Elapsed Time | Starting Balance | Interest for Period | Balance After Compounding |
|---|---|---|---|
| Year 1 | $250,000.00 | $12,500.00 | $262,500.00 |
| Year 2 | $262,500.00 | $13,125.00 | $275,625.00 |
| Year 3 | $275,625.00 | $13,781.25 | $289,406.25 |
By the end of year three, the total interest is $39,406.25, not merely $37,500.00. The difference comes from annual compounding. That gap widens as the judgment amount, rate, and collection period increase.
Why federal and state judgment interest often differ
Many people assume all judgment interest works the same way. It does not. State law may impose a fixed statutory rate, allow a contract rate, use a floating benchmark, or apply different rules to prejudgment and post judgment periods. Federal post judgment interest usually follows a Treasury linked benchmark under the federal statute. This distinction matters when evaluating forum strategy, removal consequences, settlement leverage, and reserve calculations.
For example, a state system with a fixed rate of 9% may produce a much larger post judgment number than a federal Treasury based rate in a low yield environment. In a higher yield environment, the gap may narrow. Because of that variability, accurate calculation is not just an accounting issue. It is part of legal risk analysis.
Common mistakes when calculating federal post judgment interest
- Using the wrong rate source: The correct federal rate is generally not the prime rate, contract rate, or state statutory rate.
- Changing the rate after judgment: In most federal cases, the rate is fixed by the benchmark applicable before judgment and does not reset every month or year.
- Ignoring annual compounding: Daily accrual without annual compounding can understate the true amount due on older judgments.
- Using the wrong dates: One incorrect date entry can alter the day count and the payoff amount.
- Failing to account for partial payments: If a debtor made partial payments, the unpaid principal may have been reduced, changing later interest accrual.
- Overlooking amended judgments or fee awards: Separate awards entered later may carry their own timing and calculation issues.
These issues explain why a fast estimate is valuable for planning, but a final litigation payoff statement should always be reviewed carefully.
Where to verify the legal and rate sources
For legal research and source verification, use primary or highly authoritative materials whenever possible. The following resources are especially useful:
- GovInfo publication of 28 U.S.C. § 1961
- Cornell Legal Information Institute text of 28 U.S.C. § 1961
- U.S. Treasury yield data and rate publications
Those sources help confirm both the governing federal rule and the underlying Treasury yield information used to derive the rate.
When this calculator is most useful
A federal post judgment interest calculator is especially useful in several recurring situations:
- Settlement talks after judgment: Parties can estimate the cost of waiting versus paying now.
- Payoff letters: Counsel can prepare a rough payoff range before issuing a formal demand.
- Appeal strategy: Clients can understand the financial impact of delay while appellate proceedings continue.
- Insurance and reserves: Claims professionals can model exposure on large judgments.
- Enforcement planning: Creditors can project recovery growth while pursuing collection remedies.
In all of these scenarios, speed matters. A clean calculator gives stakeholders a shared reference point and makes conversations more concrete.
Important limitations and legal caution
No calculator can substitute for legal advice tailored to a specific judgment. Questions often arise about when interest begins, what amount it runs on, how to treat costs and fees, whether the judgment was modified, and how partial satisfaction changes the ledger. Courts may also differ on certain implementation details, and individual cases can include orders that affect timing or principal amount.
Use this calculator as a high quality estimate tool. If you are filing a notice of satisfaction, objecting to a payoff demand, or presenting a damages figure to a court, confirm the legal assumptions and the exact rate source before relying on the result.
Bottom line
The federal post judgment interest calculator on this page gives you a fast and practical way to estimate what a federal money judgment may have grown to over time. By combining the judgment amount, the applicable Treasury based annual rate, the judgment date, and the payment date, you can see the projected accrued interest, total amount due, and a visual growth chart. That makes it easier to evaluate settlement timing, collection strategy, and litigation economics with much more confidence.
If your matter involves a significant balance or a disputed payoff amount, use the calculator as your first step, then verify the legal assumptions against the governing statute, docket, and published Treasury data.