Post-Judgment Interest Calculator (US federal 28 U.S.C. § 1961, daily, compounded yearly)

Understanding the post-judgment interest calculator — concept and principle

When a US court awards money, interest runs on the judgment from the day it is entered until it is paid. This calculator estimates that post-judgment interest under the federal rule of 28 U.S.C. § 1961, with daily interest compounded annually, and shows the simple-interest figure for comparison.

From 28 June 2025 to 10 November 2026 is 500 days: one full year compounded, then 135 days of simple interest.

How it is calculated

Days = payment date − judgment date.
Each 365 days counts as one year. After k full years the balance is A × (1 + r)^k.
Remaining days add simple daily interest: balance × r ÷ 365 × days left.
Post-judgment interest = final balance − judgment amount.
Simple interest without compounding = A × r × days ÷ 365.

The principle

Interest compensates the winning party for the time it waits to be paid. Under § 1961, the federal rate is the weekly average 1-year constant maturity Treasury yield, as published by the Federal Reserve, for the calendar week before the judgment. The rate is fixed for the life of the judgment, interest is computed daily and compounded annually. State courts use their own statutory rates and rules, so enter the rate that applies to your judgment.

Worked example

Default inputs: judgment 100,000 USD, rate 4.1%, judgment entered 28 June 2025, payment on 10 November 2026.

Days from judgment to payment = 500; full years compounded = 1.
After one year: 100,000 × 1.041 = 104,100 USD.
Remaining 135 days: 104,100 × 0.041 ÷ 365 × 135 ≈ 1,578.61 USD.
Post-judgment interest = 4,100 + 1,578.61 = 5,678.61 USD; total due = 105,678.61 USD.
Interest per day now = 104,100 × 0.041 ÷ 365 ≈ 11.69 USD; simple interest would be 5,616.44 USD.

Each point is the calculator re-run with only “Post-judgment interest rate (% a year)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Post-judgment interest rate (% a year)	Post-judgment interest
1.02	$1,408.00
2.05	$2,823.76
3.08	$4,247.30
4.1	$5,678.61
5.12	$7,117.69
6.15	$8,564.55
8.2	$11,481.57

How to read the result

The daily figure tells you how much the total grows for each day of delay, which helps when negotiating a payoff date. The difference between compounded and simple interest grows with time. Partial payments, court costs and attorney's fees can change the amount owed and are not included.

Common mistakes

Using today's Treasury yield instead of the rate fixed at the judgment date.
Applying the federal rule to a state-court judgment.
Forgetting that partial payments reduce the balance on which interest accrues.
Counting pre-judgment interest, which follows different rules, as post-judgment interest.

Keep in mind: This is a simplified estimate. Rules differ by court and jurisdiction; confirm the rate and method with the court clerk or a lawyer. Not legal advice.

Frequently asked questions

What is the federal post-judgment interest rate?

The weekly average 1-year constant maturity Treasury yield for the week before the judgment, published by the Federal Reserve.

Is post-judgment interest compounded?

Under 28 U.S.C. § 1961, it is computed daily and compounded annually.

Do state courts use the same rate?

No. Each state sets its own rate and rules by statute.

Sources: 28 U.S.C. § 1961 (Interest) · Board of Governors of the Federal Reserve System, H.15 Selected Interest Rates (1-year Treasury constant maturity)

Checked 9 Nov 2026. 28 U.S.C. § 1961(a)–(b), as shown by the Administrative Office of the U.S. Courts, “28 U.S.C. 1961 – Post-Judgment Interest Rates” (uscourts.gov): rate = weekly average 1-year constant maturity Treasury yield for the calendar week preceding the judgment; interest computed daily to the date of payment and compounded annually.

Your numbers