Pre-Judgment Interest Calculator
When a court awards damages, interest usually runs from the date the claim arose, not the date of the verdict. This pre-judgment interest calculator takes the award amount, the applicable statutory rate, and the start and end dates, then counts the exact days and computes the interest owed.
Quick Answer
A $50,000 award at 10% annual interest accruing from January 15, 2024 to July 15, 2025 earns $7,493.15 of pre-judgment interest over 547 days, for a total of $57,493.15. That is $13.70 per day, adding 14.99% to the award before a single day of post-judgment interest runs.
- The rate is statutory, not negotiated. Each jurisdiction sets its own rate: California 10%, New York 9%, Florida varies by statute, federal courts use the T-bill rate.
- Days are exact, not estimated. The calculator counts actual calendar days between your dates, including leap days, because a 547-day accrual differs from "about 18 months".
- Pre-judgment interest is usually simple. Most statutes award simple interest only; compounding requires explicit statutory authority.
- This is not legal advice. Start dates, rate changes, and tolling rules vary by claim type and jurisdiction; confirm with counsel before relying on a figure.
What pre-judgment interest is (and is not)
Pre-judgment interest compensates the winning party for the time value of money between the date the claim arose and the date of judgment. The defendant had the use of money that rightfully belonged to the plaintiff, so the award grows to make the plaintiff whole as of the judgment date.
It is distinct from post-judgment interest, which runs after the judgment is entered and is governed by separate statutes: 28 U.S.C. Section 1961 sets the federal post-judgment rate at the weekly average 1-year Treasury bill yield. Pre-judgment interest is also not a penalty; it is restitution for delay, and courts in many jurisdictions award it as of right in contract cases while treating it as discretionary in tort cases.
The statutory rate table: it depends where you sue
There is no national pre-judgment rate. The number to enter depends on the court and the claim, and some statutes change the rate over time, so always verify the current figure.
| Jurisdiction | Rate | Basis |
|---|---|---|
| California | 10% per year | Civil Code 3289(b) for contract claims without a stipulated rate; CCP 685.010 sets the same 10% on money judgments once entered |
| New York | 9% per year | CPLR 5004, from the earliest ascertainable date |
| Florida | Varies quarterly | Section 55.03 sets the rate each quarter |
| Texas | Statutory formula | Finance Code Section 304.003, tied to the prime rate |
| Federal courts | T-bill yield | 28 U.S.C. 1961, weekly average 1-year Treasury yield |
The example uses California's 10%: $50,000 × 10% × (547/365) = $7,493.15. At New York's 9% the same period yields $6,743.84; at a 4% federal-style rate it yields $2,997.26. The jurisdiction choice alone can swing the figure by thousands, which is why rate selection is the highest-stakes input on this page. If the dispute involves collecting on an existing obligation, our debt collection interest calculator covers the contractual-interest side.
The day-count detail that moves the money
Interest accrues per day: $50,000 at 10% earns $13.70 every day the case runs. Over 547 days that is $7,493.15; a case that settles six months earlier saves roughly $2,500 in interest alone. This daily bleed is why pre-judgment interest shapes settlement strategy: defendants face a growing meter, while plaintiffs can afford patience.
Claim accrues or action filed; the meter starts running.
$13.70 accrues on a $50,000 award at 10%. Leap days count.
Pre-judgment interest stops; post-judgment interest begins under a new statute.
Two subtleties to watch. First, some statutes toll interest during periods of plaintiff-caused delay, so the accrual window is not always the full case length. Second, rate changes mid-case: Florida's quarterly rate means a multi-year case accrues at several different rates, which this calculator's single-rate model approximates. For long Florida cases, compute each quarter separately and add them.
What the verdict badge is telling you
The calculator labels every result by how large the interest is next to the award itself. Under 5% of the award is Small, 5% to under 15% is Material, and 15% or more is Large. The worked example sits at 14.99%, so it reads Material, but only just: a 548th day would push the same award to 15.01% and a Large badge.
Read the badge as a settlement signal, not a legal conclusion. A Small accrual rarely changes what either side will accept, because the interest is a footnote next to the award. A Material accrual is real negotiating weight: the meter is visible enough that delay costs the paying side something worth conceding. A Large accrual can rival a second claim in size, which is when the paying side has the strongest reason to settle early and the receiving side can most afford patience. The badge never changes the math; it only names how much the math matters.
| Badge | Interest as share of award | What it usually means |
|---|---|---|
| Small | Under 5% | Interest is a footnote next to the award. |
| Material | 5% to under 15% | Delay carries visible negotiating weight. |
| Large | 15% or more | Interest rivals a second claim in size. |
When judgment is finally entered, this meter stops and a different one starts: post-judgment interest runs under its own statute, federally at the weekly average 1-year Treasury bill yield under 28 U.S.C. 1961. The pre-judgment figure the calculator produces is the amount owed up to that handoff, not beyond it.
What most pre-judgment calculators miss
Competing tools usually ask for a number of years rather than actual dates, which hides the day-count precision that real practice demands. This calculator takes real calendar dates, counts exact days including leap years, and reports the daily accrual so the settlement-meter effect is visible. The other common gap is the rate: most calculators default to a single rate with no guidance, while the correct rate is a jurisdictional question. The table above gives the major starting points, with citations to the actual statutes. For the simple-interest math behind the scenes, our cost of interest calculator breaks down the same P × r × t formula, and our basic loan calculator covers interest on ordinary borrowing.
Frequently Asked Questions
Pre-judgment interest is interest added to a court award for the period between when the claim arose and when judgment is entered. It compensates the winning party for the time value of money during the case.
Award amount times the statutory annual rate times the number of days divided by 365. A $50,000 award at 10% over 547 days earns $7,493.15. Most statutes use simple interest, so there is no compounding.
It depends on the jurisdiction and claim type. California uses 10% for contract claims under Civil Code 3289(b) where the contract sets no rate, New York 9% under CPLR 5004, Florida sets a quarterly rate under Section 55.03, and federal courts use the T-bill yield under 28 U.S.C. 1961. Confirm the current rate with counsel.
Usually from the date the claim accrued or the action was filed, depending on the statute. In New York, for example, interest runs from the earliest ascertainable date the cause of action existed. Some statutes toll interest during periods of plaintiff-caused delay.
Almost always simple. Compound pre-judgment interest requires explicit statutory authority, which most jurisdictions do not grant. The calculator uses simple interest on the award amount only.
Pre-judgment interest covers the period before judgment and is set by state statutes or court discretion. Post-judgment interest runs after judgment is entered; in federal court it is set by 28 U.S.C. 1961 at the weekly average 1-year Treasury bill yield.
No. In many jurisdictions it is available as of right in contract and liquidated-damages cases but discretionary in tort cases, where courts weigh factors like the clarity of the damages and each side's conduct. An attorney can tell you whether your claim qualifies.
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References
- Terms.Law. California Judgment Interest: Your $10K Judgment Becomes $20K. Accessed October 25, 2026.
- Cornell Law Institute. 28 U.S.C. Section 1961: Interest. Accessed October 25, 2026.
- Texas Legislature. Finance Code Section 304: Interest on Judgments. Accessed October 25, 2026.
- Florida Senate. Section 55.03: Judgments; Rate of Interest. Accessed October 25, 2026.
- Justia. California Civil Code Section 3289. Accessed October 25, 2026.
- Cornell Law Institute. Federal Rules of Civil Procedure, Rule 54: Judgments. Accessed October 25, 2026.
- LegalClarity. California Prejudgment Interest in a Breach of Contract Case. Accessed October 25, 2026.
- LegalClarity. California Civil Code 3287: Prejudgment Interest Rules. Accessed October 25, 2026.
- U.S. Courts. Post-Judgment Interest Rate. Accessed October 25, 2026.
- New York State Senate. CPLR Section 5001: Interest to Verdict, Report or Decision. Accessed October 25, 2026.