To use a judgment calculator or run the math yourself, you stack five layers: the principal awarded, pre-judgment interest, post-judgment interest that accrues daily until payment, taxable court costs, and attorney’s fees when a contract or statute allows them. The announced verdict is almost never the final number. Each layer follows its own rules, and the rates depend on whether your case sits in federal or state court.
Start With the Principal
The principal is the dollar figure a judge or jury awarded, or the amount in a court-approved settlement. It covers whatever the prevailing party proved: out-of-pocket losses like medical bills and lost income, non-economic harm like pain and suffering, or both. This is the base. Everything else layers on top of it.
Add Pre-Judgment Interest
Pre-judgment interest compensates the winner for the time between when the harm happened and when the court entered the judgment. Lawsuits take months or years, and without this interest the losing party would benefit from delay. The clock usually starts on the date the claim arose, such as the date of an injury or a contract breach, though some jurisdictions start it on the filing date instead.
The rate is set by statute and varies widely. Some states lock in a fixed percentage. Others tie the rate to a financial benchmark like the prime rate or a Treasury yield. The rate can also differ by case type: a breach-of-contract claim and a personal injury claim in the same state may carry different pre-judgment rates.
Compounding depends on jurisdiction. Several states use simple interest, which accrues only on the original principal. Others compound annually. On a large judgment that took years to litigate, the difference is substantial. The simple formula: multiply the principal by the annual rate, then by the number of years (or fraction) between the accrual date and the judgment date. Courts in most jurisdictions exclude damages for future losses from this calculation, since those costs had not been incurred yet.
Add Post-Judgment Interest
Once the court enters the judgment, post-judgment interest starts accruing immediately and keeps running until the debtor pays in full.
In federal court, the rate is pegged to the weekly average one-year constant maturity Treasury yield published by the Federal Reserve Board for the calendar week before the judgment date.1Office of the Law Revision Counsel. 28 USC 1961 – Interest As of late March 2026, that rate sits at 3.70%.2United States Courts. 28 USC 1961 – Post Judgment Interest Rates The rate locks in on the judgment date and stays fixed for the life of that judgment, even if Treasury yields move later.
Federal post-judgment interest is computed daily and compounded annually.1Office of the Law Revision Counsel. 28 USC 1961 – Interest To get the daily accrual, take the total judgment at entry (principal plus any pre-judgment interest and costs), multiply by the annual rate, and divide by 365. Multiply by the number of days since entry.
State post-judgment rates follow their own rules and often differ from the federal number. Some states set rates in the 8% to 10% range, well above what federal courts charge. For a state court judgment, check that state’s statute for the applicable rate and whether it compounds.
Add Taxable Court Costs
The winning party can recover certain litigation expenses on top of the judgment. In federal court, the categories are set by statute: clerk and marshal fees, transcript fees for depositions and hearings, witness fees and expenses, and the cost of copies necessarily obtained for the case.3GovInfo. 28 USC 1920 – Taxation of Costs State courts follow their own cost statutes, with generally similar categories.
The prevailing party files a bill of costs with the court clerk.3GovInfo. 28 USC 1920 – Taxation of Costs Once approved, the costs are folded into the enforceable judgment and start accruing post-judgment interest along with everything else.
Add Attorney’s Fees When They Apply
The default in American courts is that each side pays its own lawyer. The exceptions can swamp every other line in the calculation.
The most common exception is a contract with a fee-shifting clause. If the underlying agreement says the losing side pays the other party’s legal fees, courts generally enforce that provision. Attorney’s fees often dwarf the other components of a judgment, so this is worth checking first.
Federal statutes override the default in specific categories of cases. Civil rights actions are a prominent example: a court can award reasonable attorney’s fees to the prevailing party in cases brought to enforce federal civil rights protections.4Office of the Law Revision Counsel. 42 USC 1988 – Proceedings in Vindication of Civil Rights Similar fee-shifting provisions exist in consumer protection, employment, and environmental statutes at the federal and state level.
Courts can also order fee payment as a sanction for litigation abuse, such as frivolous filings or discovery misconduct. These are discretionary and harder to predict. In federal court, a motion for attorney’s fees must be filed within 14 days after entry of judgment unless a statute or court order says otherwise.5Legal Information Institute. Federal Rules of Civil Procedure Rule 54 – Judgment; Costs
A Worked Example
Suppose a federal court enters a $100,000 judgment on January 1, with $8,000 in pre-judgment interest already calculated and $3,000 in approved court costs. The total at entry is $111,000. At a locked-in post-judgment rate of 3.70%, the daily accrual is:
$111,000 × 0.037 ÷ 365 = $11.25 per day
After 180 days with no payment, the debtor owes roughly $113,025. Wait a full year and the interest alone adds about $4,107 to the balance, slightly more once annual compounding kicks in. On larger judgments, or at the higher rates some state courts charge, delay becomes expensive quickly.
Recalculating After Partial Payments
Post-judgment interest accrues only on the unpaid balance. When the debtor makes a partial payment, split the calculation into time periods based on payment dates.
Using the example above, say the debtor pays $50,000 on day 90. Calculate interest on the full $111,000 for days 1 through 90, then reduce the principal to $61,000 and calculate interest on that lower amount going forward. The daily rate for the second period drops to $61,000 × 0.037 ÷ 365 = $6.19. Each subsequent payment creates a new period with a new, lower per diem.
Keep a running ledger with four columns: date, payment amount, remaining balance, and per diem interest rate. Rounding errors across multiple payments and long time periods can add up to real money.
How Long Interest Keeps Running
Judgments do not last forever. In most states, a money judgment stays enforceable for somewhere between 5 and 20 years, with 10 years the most common initial period. Many states allow renewal for an additional period of similar length, but only if the creditor files the renewal paperwork before the original judgment expires. Miss the deadline and the judgment becomes unenforceable. Once expired, it cannot be revived.
Federal judgment liens last 20 years and can be renewed for one additional 20-year period, provided a notice of renewal is filed before the original period runs out and the court approves it.6Office of the Law Revision Counsel. 28 USC 3201 – Judgment Liens Interest keeps accruing throughout the enforceable period, which is why stale judgments sometimes balloon to multiples of the original award by the time the creditor moves to collect.
Why Collection Speed Changes the Total
Federal law caps the amount that can be garnished from a debtor’s wages. The maximum is the lesser of 25% of weekly disposable earnings or the amount by which those earnings exceed 30 times the federal minimum wage of $7.25 per hour, which fully protects the first $217.50 per week.7Office of the Law Revision Counsel. 15 USC 1673 – Restriction on Garnishment If a debtor’s weekly disposable earnings are $217.50 or less, garnishment is not allowed at all. Some states impose tighter limits. These caps directly affect how long it takes to satisfy a judgment through wage garnishment, and longer timelines mean more post-judgment interest piled onto the total.