Federal Court Post Judgment Interest Calculator
Estimate post judgment interest under 28 U.S.C. § 1961 using the judgment amount, the annual Treasury based rate, and the time between judgment and payment. This calculator applies daily accrual with annual compounding to model how a federal money judgment grows over time.
How federal court post judgment interest works
Federal court post judgment interest is the statutory interest that accrues on a money judgment after the court enters judgment and before the judgment is fully paid. In federal practice, lawyers, claims professionals, in house legal teams, and judgment creditors often need to know not only the principal amount awarded, but also the running balance that continues to grow while payment is pending. That extra amount can materially affect settlement leverage, collection strategy, reserve calculations, and the final satisfaction amount.
The governing federal statute is 28 U.S.C. § 1961. In general terms, it ties post judgment interest to the weekly average 1-year constant maturity Treasury yield for the calendar week preceding the date of judgment. Interest is computed daily to the date of payment and is compounded annually. Those details matter. A federal judgment is not usually a flat simple interest number that you can estimate casually. The rate source is specific, the accrual is daily, and unpaid interest effectively capitalizes once per year.
This calculator is designed to help you model that process. You enter the judgment principal, the annual rate, the date judgment was entered, and the date payment will be made. The calculator then estimates the interest accrued, the total payoff amount, the elapsed days, and a balance path chart so you can visualize growth over time.
What rate applies under federal law
In most federal cases, the correct post judgment interest rate is not an arbitrary rate selected by a party. It is generally the weekly average 1-year constant maturity Treasury yield, as published by the Federal Reserve, for the calendar week preceding the date of judgment. That means timing matters. A judgment entered one week later may carry a different statutory rate. In a low yield environment, post judgment interest can be modest. In a higher yield environment, it can become financially significant very quickly, especially on large judgments.
If you need the official source material, review: 28 U.S.C. § 1961 on the U.S. Code website, the Federal Reserve H.15 interest rate release, and U.S. Treasury resources.
Key legal mechanics
- The interest rate is typically fixed as of the judgment date based on the prior calendar week’s 1-year constant maturity Treasury yield.
- Interest accrues daily from the date of entry of judgment until payment.
- Interest is compounded annually, not monthly and not continuously.
- The statute applies to money judgments in federal court, but case specific orders and procedural history can still matter.
- If there are amended judgments, partial satisfactions, appeals, or post trial motions, the accrual analysis may require a more careful timeline review.
Inputs you need before calculating
To calculate federal court post judgment interest accurately, gather four core data points. First, identify the principal amount on which post judgment interest runs. Second, confirm the exact date the judgment was entered on the docket. Third, determine the applicable statutory annual rate from the appropriate Treasury based source. Fourth, choose the payoff or evaluation date. If you are preparing a demand letter, reserve summary, or settlement proposal, the evaluation date may be today. If you are preparing a satisfaction amount, it may be the expected wire date or check date.
Checklist for practitioners
- Read the judgment carefully and confirm the amount of the money judgment.
- Verify the entry date from the federal docket, not from memory or a draft order.
- Pull the weekly average 1-year constant maturity Treasury yield for the calendar week preceding judgment.
- Confirm whether there were later modifications, remittitur, offsets, or partial payments.
- Run the calculation through the anticipated payment date and document your assumptions.
Why annual compounding changes the final number
Many people informally estimate judgment interest by multiplying principal by rate by time. That approach can be directionally useful for short periods, but it can understate the real amount due in longer federal cases because the statute calls for annual compounding. Daily accrual means interest accumulates every day. Annual compounding means that once each year passes, the accrued interest is added to principal and future interest begins to accrue on that larger balance.
The effect becomes more visible as either the principal or the rate rises. On a six figure or seven figure judgment, even a small difference in method can become meaningful. For accounting, settlement negotiation, and enforcement planning, that precision matters.
| Sample Judgment | Rate | 1 Year Approximate Balance | 3 Year Approximate Balance | 5 Year Approximate Balance |
|---|---|---|---|---|
| $100,000 | 0.50% | $100,500.00 | $101,507.51 | $102,525.13 |
| $100,000 | 3.00% | $103,000.00 | $109,272.70 | $115,927.41 |
| $100,000 | 5.00% | $105,000.00 | $115,762.50 | $127,628.16 |
The figures above are practical illustrations of how growth changes across different statutory rates. They are useful because Treasury linked rates can vary substantially over time. When the 1-year Treasury environment is near zero, post judgment interest may be relatively small. When Treasury yields increase, the carrying cost of an unpaid judgment increases with them. That can materially alter the economics of delay.
Daily accrual versus simple annual math
Federal post judgment interest is often described in shorthand as an annual rate, but the statute expressly provides for daily computation to the date of payment. In real world terms, that means the payoff amount on a Wednesday differs slightly from the payoff amount on the next Friday. When counsel exchanges payoff letters, a precise as of date is critical. If funds are delayed, the number should be updated.
The next table shows why compounding can push the total above a simple interest estimate over time. The numbers below use a sample $250,000 judgment at a 4.00% annual rate.
| Time Unpaid | Simple Interest Only | Balance with Annual Compounding | Difference |
|---|---|---|---|
| 1 Year | $260,000.00 | $260,000.00 | $0.00 |
| 3 Years | $280,000.00 | $281,216.00 | $1,216.00 |
| 5 Years | $300,000.00 | $304,166.50 | $4,166.50 |
On larger judgments, those differences can become much larger. If the underlying award is $5 million instead of $250,000, even small percentage differences in the rate or the methodology can shift the payoff amount by tens of thousands of dollars. That is why finance teams and litigators often document the calculation method in writing and refresh the payoff figure immediately before tender.
Common issues that affect federal judgment interest
1. Partial payments
If the judgment debtor makes a partial payment, the calculation usually changes as of that payment date. The remaining unpaid balance continues to accrue. A single start to finish calculation can overstate or understate the true amount due if you ignore partial satisfactions.
2. Amended or corrected judgments
Whether an amended judgment changes the interest start date can depend on the nature of the amendment and the procedural posture of the case. A purely clerical correction may not have the same effect as a materially revised monetary award. When there is doubt, the relevant orders and governing case law should be reviewed.
3. Costs and fees
In some cases, attorney fees, taxable costs, or sanctions are added at different times. That raises the question of what amount bears interest and from what date. The answer can be straightforward in some matters and highly fact specific in others.
4. State law confusion
Parties sometimes mix state judgment interest rules with federal rules. That is a common source of error. Federal post judgment interest on federal judgments is generally governed by the federal statute, even if the case involved state law claims. There can be nuance, but you should not assume a state statutory rate applies.
5. Appeals and stays
An appeal does not automatically eliminate post judgment interest exposure. Depending on the circumstances, interest may continue while the case is on appeal unless payment or a supersedeas arrangement changes the practical collection picture. Because these issues can become high stakes, parties often revisit the projected exposure during appellate mediation or settlement discussions.
How to use this calculator effectively
This calculator is best used as a practical estimate tool. Start with the exact principal amount stated in the judgment. Enter the annual rate that corresponds to the week preceding the judgment date. Then enter the judgment date and the anticipated payment date. The tool will estimate:
- Total accrued post judgment interest
- Total payoff amount
- Elapsed days
- Approximate effective growth over the selected period
- A chart showing how the balance increases over time
If you expect a payment in stages, run the calculator through the first payment date, reduce the principal accordingly, and then run a second calculation for the remaining balance. That approach is usually closer to the true economics than a single uninterrupted estimate.
Worked example
Assume a federal court enters a $425,000 money judgment on March 1. The applicable Treasury based rate for the calendar week preceding judgment is 4.80%. The debtor pays on September 1 of the following year. Because the rate is fixed from the judgment date, you do not change the rate every month. Instead, you allow interest to accrue daily from March 1 to the payment date, and if a full year passes before payment, the accrued interest compounds into principal on the anniversary. A tool like this calculator makes that timeline much easier to model than trying to approximate it manually in email or on a legal pad.
Best practices for documentation
- Include the statutory citation in any payoff or demand communication.
- State the exact annual rate used and where it came from.
- State the exact through date of the calculation.
- Document whether your model uses actual calendar days or a fixed 365-day basis.
- Update the figure immediately before settlement funding or satisfaction filing.
Authoritative sources worth checking
When you need to verify the law or the underlying Treasury rate source, start with primary or institutional materials. The most useful references include the U.S. Code text for 28 U.S.C. § 1961, the Federal Reserve H.15 release for Treasury constant maturity data, and federal judiciary procedural materials where relevant. Those sources are far more reliable than generic forum posts or unsourced blog summaries.
Final takeaway
Federal court post judgment interest calculation is straightforward in principle but easy to misstate in practice. The correct rate is tied to the weekly average 1-year constant maturity Treasury yield for the calendar week preceding judgment. The interest accrues daily, compounds annually, and continues until payment. Even when the rate seems small, the unpaid balance can become meaningful over time, especially in larger commercial disputes, class action fee awards, sanctions orders, and substantial damages judgments.
Use the calculator above as a precise working estimate, but remember that unusual procedural facts can change the legal analysis. If the judgment has been modified, partially satisfied, appealed, or supplemented by later fee and cost awards, a case specific review is the prudent next step.