Post Judgment Interest Calculator

Q: What is the difference between pre-judgment and post-judgment interest?

Pre-judgment interest covers the time between the date of the harm (like a breach of contract or an injury) and the date the court enters the judgment. It is often argued about in court and is not always allowed. Post-judgment interest covers the time after the judgment is entered. It is almost always automatic and set by statute. Pre-judgment interest is usually folded into the judgment amount. After that, post-judgment interest grows on that whole total.

Q: How do partial payments change the interest on a judgment?

Most courts follow the U.S. Rule : a payment goes first to the interest that has already built up, and only the leftover goes to the principal. Example: you owe $10,000 with $500 in accrued interest and pay $2,000. The first $500 clears the interest, and $1,500 cuts the principal to $8,500. Daily interest then grows on $8,500. So small payments can barely touch the principal if the interest rate is high.

Q: Is post-judgment interest compounded daily?

Almost never. Interest is calculated daily, but that is not the same as compounding daily. Most state judgments use simple interest, so the daily amount never changes unless a payment lowers the balance. Federal judgments under 28 U.S.C. § 1961 are compounded once a year. Daily compounding on a judgment is rare and would need a statute or a contract that clearly allows it.

Post Judgment Interest Calculator

Introduction

When a court enters a money judgment, the amount owed does not stay the same. Interest keeps adding up each day until the debt is paid. This Post Judgment Interest Calculator shows you how much that interest is worth today.

Just enter the judgment amount, the yearly interest rate, and the two dates: the day the court entered the judgment and the day you want to count through. The calculator then gives you the daily interest, the number of days that have passed, the total interest earned, and the full amount now owed.

You can pick simple interest or compound interest, and choose a day-count basis of 365 days, 360 days, or actual days. Most federal post-judgment interest uses simple interest, but state rules can differ, so check the law where your case is filed.

Along with the totals, you get a step-by-step math breakdown, a chart of how the balance grows, and a year-by-year table. Use them to check the numbers, plan a payoff, or explain the amount to a client, a judge, or the other side.

How to use our Post Judgment Interest Calculator

Enter your judgment amount, the interest rate, how days are counted, the interest method, and your two dates. The calculator shows your daily interest, days elapsed, total interest accrued, and the total judgment value you are owed, plus a step-by-step solution, a chart, and a year-by-year table.

Judgment Amount: Type the dollar amount the court awarded. This is the starting principal that interest is charged on.

Annual Interest Rate (%): Type the post-judgment interest rate for your case. Federal and state rates differ, so check the rule in your court before you enter it.

Day-Count Basis: Pick how many days make up a year. Choose 365 days, Actual/Actual (365 or 366 in leap years), or 360 days. This sets the daily interest rate.

Interest Calculation Method: Choose Simple Interest to earn interest only on the original amount, or Compound (Annual) to earn interest on the amount plus past interest each year. Most U.S. federal judgments use simple interest.

Judgment Date: Enter the month, day, and year the court entered the judgment. Interest starts on this date.

Calculate Interest Through: Enter the month, day, and year you want the interest counted to. This is often today's date or a planned payoff date.

Click Calculate to see your results. Click Reset to clear your entries and start over.

What Is Post-Judgment Interest?

When a court decides someone owes money, that decision is called a judgment. Post-judgment interest is the extra money that builds up on that award from the day the judgment is entered until the day it is paid. It exists so the winning side does not lose value while waiting, and so the losing side has a reason to pay fast.

How Post-Judgment Interest Works

Interest grows on the judgment each day. Take the judgment amount, multiply it by the yearly rate, then divide by the number of days in the year. That gives the daily interest. Multiply the daily interest by the number of days that have passed, and you get the total interest owed.

Example: a $100,000 judgment at 5% per year with a 365-day basis earns about $13.70 per day. After one full year, that is about $5,000 in interest, for a total of $105,000.

Interest Rates Are Set by Law

You usually cannot pick the rate. Federal courts use a rate tied to the weekly average one-year Treasury yield, which changes often and is published by the courts. State courts set their own rates by statute. Some states use a fixed number, like 9% or 10%. Others use a floating rate that moves with the market. Always check the rules in the state or court that issued your judgment.

Simple vs. Compound Interest

Simple interest grows only on the original judgment amount. Compound interest grows on the judgment plus the interest already added, so it builds faster. Most U.S. federal judgments use simple interest, though federal law does allow annual compounding. Many states also require simple interest. Use the method your court or statute calls for.

Day-Count Basis

The day-count basis decides how a yearly rate turns into a daily rate. A 365-day basis is the most common. Actual/Actual uses 366 days in leap years, which makes the daily amount slightly smaller in those years. A 360-day basis makes each day worth a little more. The basis you choose can change the final number, so match it to your court's rule.

Why It Matters

Interest can add up to thousands of dollars over time. Knowing the daily rate helps lawyers, creditors, and debtors figure out an exact payoff amount for any date. It also helps both sides decide whether to settle now or keep waiting. Interest usually stops the day the judgment is paid in full, and partial payments lower the balance that interest grows on.

Formulas used

Days Elapsed Between Judgment Date and As-Of Date

N = \frac{t_{\text{end}} - t_{\text{judgment}}}{86{,}400{,}000\ \text{ms/day}}

Daily Interest Amount

I_{\text{day}} = \frac{P \times r}{D}, \qquad r = \frac{\text{rate \%}}{100}

Elapsed Time in Years (Day-Count Fractions by Period)

T = \sum_{k=1}^{n} \frac{d_k}{D_k}, \qquad D_k \in \{360,\ 365,\ \text{actual days in year } (365 \text{ or } 366)\}

Total Simple Interest Accrued

I = P \times r \times T = P \times r \times \sum_{k=1}^{n} \frac{d_k}{D_k}

Compound (Annual) Balance Growth per Period

B_k = B_{k-1}\left(1 + r \times \frac{d_k}{D_k}\right), \qquad B_0 = P, \qquad I = B_n - P

Interest Earned in a Single Period

I_k = B_{\text{base},k} \times r \times \frac{d_k}{D_k}, \qquad B_{\text{base},k} = \begin{cases} P & \text{simple} \\ B_{k-1} & \text{compound} \end{cases}

Total Judgment Value Owed

V = P + I

Frequently asked questions

When does post-judgment interest start and when does it stop?

Interest usually starts the day the court enters the judgment, not the day the lawsuit was filed or the day of the injury. It keeps adding up every day until the judgment is paid in full.

If the debtor pays part of the money, interest keeps running on what is still owed. When the last dollar is paid, interest stops.

Some states start interest on a slightly different date, such as the day the judgment is recorded, so check your state rule.

What is the difference between pre-judgment and post-judgment interest?

Pre-judgment interest covers the time between the date of the harm (like a breach of contract or an injury) and the date the court enters the judgment. It is often argued about in court and is not always allowed.

Post-judgment interest covers the time after the judgment is entered. It is almost always automatic and set by statute.

Pre-judgment interest is usually folded into the judgment amount. After that, post-judgment interest grows on that whole total.

Does post-judgment interest keep adding up during an appeal?

Yes. Filing an appeal does not pause interest. In most courts, interest keeps running from the original judgment date, even while the appeal is pending.

This is one reason a losing party may post a bond or pay the money into the court. Doing so can stop or limit more interest from piling up.

If the appeal cuts the award, interest is usually recalculated on the new, lower amount from the original judgment date.

How do partial payments change the interest on a judgment?

Most courts follow the U.S. Rule: a payment goes first to the interest that has already built up, and only the leftover goes to the principal.

Example: you owe $10,000 with $500 in accrued interest and pay $2,000. The first $500 clears the interest, and $1,500 cuts the principal to $8,500. Daily interest then grows on $8,500.

So small payments can barely touch the principal if the interest rate is high.

What is per diem interest on a judgment?

Per diem means "per day." It is the dollar amount of interest a judgment earns each day.

The formula is:

Per diem = judgment amount × yearly rate ÷ days in year

A $50,000 judgment at 6% with a 365-day year earns $50,000 × 0.06 ÷ 365 = $8.22 per day.

Lawyers use the per diem to quote an exact payoff figure for any future date. Payoff letters often say something like "plus $8.22 per day after this date."

Does post-judgment interest apply to attorney fees and court costs?

Usually yes, if those fees and costs are written into the judgment itself. Interest grows on the whole judgment amount, not just the damages part.

The timing can matter. If attorney fees are awarded later in a separate order, some courts start interest on that piece from the later date instead.

Read the judgment paper closely to see what totals are included and what dates apply.

Is post-judgment interest compounded daily?

Almost never. Interest is calculated daily, but that is not the same as compounding daily.

Most state judgments use simple interest, so the daily amount never changes unless a payment lowers the balance. Federal judgments under 28 U.S.C. § 1961 are compounded once a year.

Daily compounding on a judgment is rare and would need a statute or a contract that clearly allows it.

How long can a judgment keep earning interest?

It depends on the state. Judgments are good for a set number of years, often 5, 7, 10, or 20.

Many states let the creditor renew the judgment before it expires. When it is renewed, interest keeps running, and in some states the unpaid interest is rolled into the new principal.

If the judgment expires and is not renewed, both the debt and the interest stop being collectible.

Can the parties agree to a different post-judgment interest rate?

Sometimes. If the case came from a contract that set an interest rate, many courts will apply that contract rate instead of the statutory one, as long as it is legal and not too high.

Parties can also agree to a lower rate or to waive interest as part of a settlement. That deal should be written into the judgment or the settlement papers.

Without an agreement or a contract term, the statutory rate applies by default.

Is post-judgment interest taxable?

Generally yes. Interest you receive on a judgment counts as interest income and is taxable, even when the underlying award is not.

For example, money for a physical injury is often tax-free, but the interest that grew on it is still reported as income. The payer may send a Form 1099-INT.

Tax rules can be tricky, so ask a tax professional about your case.

How much interest does a $10,000 judgment earn in a year?

It depends on the rate. With simple interest and a 365-day year:

4% → $400 a year, about $1.10 a day
6% → $600 a year, about $1.64 a day
9% → $900 a year, about $2.47 a day
12% → $1,200 a year, about $3.29 a day

At 9%, a $10,000 judgment left unpaid for five years grows by $4,500 in interest alone.

Who decides which post-judgment interest rate applies to my case?

The law of the court that entered the judgment decides. Federal district courts use the rate in 28 U.S.C. § 1961, which is tied to the weekly average one-year Treasury yield. State courts follow their own statutes.

To find your rate, look at these in order:

The judgment document, which sometimes states the rate
Your state's judgment interest statute
The court clerk's office or court website

Using the wrong rate can throw off a payoff amount by thousands of dollars.

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