Prejudgment Interest Rules in Oregon

At a glance

Requirements one by one

Governing law

ORS 82.010(1)(a) is the entire statutory basis: it sets a 9% rate "payable on ... [a]ll moneys after they become due." Oregon has never enacted a separate prejudgment-interest statute for tort claims, or a separate one for contract claims, everything runs through this one general interest provision. What actually decides whether a given claim gets prejudgment interest is not the statute's text (which doesn't mention "prejudgment interest" at all) but a long line of Oregon Court of Appeals and Supreme Court decisions construing it, starting with Krieg v. Union Pac. Land Resources Corp. (1974) and continuing through Strader v. Grange Mutual Ins. Co. (2002), Miller v. C.C. Meisel Co. (2002), and Spaid v. 4-R Equipment (2012).

Interest rate

9% a year by default under ORS 82.010(1), but that default only applies "if the parties have not otherwise agreed to a rate of interest." If there's a written contract that sets its own rate, that rate controls instead, even if it's far above 9%; courts do still police an extreme contract rate as an unenforceable penalty in egregious cases.

When interest starts running

For a contract debt, from the date the money became due. For a claim where the amount wasn't fixed by agreement, most tort claims, and any contract claim without a stated price, from the date the damages became ascertainable: a sum certain, or a figure calculable from a known formula or standard. Oregon courts have been explicit that this can be an earlier date than the date of judgment, or even earlier than the date a jury resolves disputed facts, because "even though damages are not ascertainable until issues of fact have been decided [by the jury], prejudgment interest is proper", the jury's later fact-finding can retroactively confirm an amount that was always calculable from an earlier, fixed date.

Contract vs. tort claims

Oregon draws no formal line between contract and tort claims for this purpose, both run through the same statute and the same two-part ascertainability test: (1) is the exact amount of damages ascertained or readily ascertainable, and (2) is the date interest should start easily ascertained? In practice, that produces a pattern that looks similar to a contract/tort split without actually being one: a fixed contract debt almost always clears the test, while a personal-injury claim for pain and suffering almost never does, because there's no formula to price it before verdict. But a tort claim for property damage with a known repair cost, or a business tort with a contractually defined damages formula, clears the same test a contract claim would.

Mandatory or discretionary

Mandatory as a matter of law once ascertainability is established, Oregon courts describe the determination of the accrual date and the calculability of the amount as questions decided "as a matter of law," not questions of equitable discretion for the judge to weigh. The one place discretion-like uncertainty enters is procedural: if the facts needed to fix the date or the amount are genuinely disputed between the parties, that threshold factual question belongs to the jury, and a court can't award prejudgment interest without a jury finding (or an undisputed record) resolving it first.

Simple or compound

ORS 82.010(2)(b) calls interest on a judgment simple unless a contract provides otherwise. The quoted subsection (1)(a), which supplies the nine-percent prejudgment default, does not expressly specify compounding. The cited federal order applied simple prejudgment interest in its case, but it does not establish a universal state-law rule for every contract.

Claims against the government

The Oregon Supreme Court's decisions in Newport Church and Young explain that the general interest statute does not itself waive the state's interest immunity. The quoted rule in Newport Church recognizes consent through an act of the legislature or a lawful contract of executive officers. The cases distinguish cities from the state and counties. A claimant must identify the authority that permits interest against a particular public defendant.

Other exceptions

The agreed contract rate displaces the nine-percent default where the agreement is enforceable. A compounding term calls for a separate contract analysis. Separately, ORS 82.010(2)(f) sets a special, lower interest rate (the lesser of 5% a year or 3% over the Federal Reserve discount rate) for judgments in medical-malpractice cases, but that's a POSTjudgment rate only, inside the different subsection (2) that governs interest after judgment is entered. It has nothing to do with prejudgment interest and is an easy trap for anyone skimming the statute.

What trips people up

Assuming ORS 82.010 is a contract-only statute, because it never uses the words "tort" or "prejudgment," is the single biggest misreading. The statute is claim-type neutral; the ascertainability test built on top of it by case law is what actually sorts claims, and it sorts by whether the damages have a knowable number and date, not by the label on the complaint.

Confusing the special medical-malpractice rate in ORS 82.010(2)(f) with a general prejudgment rate is a second trap: that lower rate is postjudgment-only, and it applies regardless of whether the defendant is the medical professional personally or another party found liable for the professional negligence.

Assuming the state waived its interest immunity just by allowing itself to be sued at all is a third trap. Oregon's courts have rejected that inference repeatedly: submitting to liability for the underlying claim is not the same as consenting to pay interest on it, and the general interest statute doesn't supply that consent by itself.

Common questions

What's Oregon's prejudgment interest rate? 9% a year under ORS 82.010(1), unless a written contract sets a different rate.

Can I get prejudgment interest on an Oregon personal injury claim? Only if the damages are ascertainable, a fixed or formula-calculable amount as of an identifiable date. Ordinary pain-and-suffering damages usually aren't, because a jury sets that figure without a fixed formula; a property-damage claim with a known repair cost is more likely to qualify.

Does Oregon prejudgment interest compound? ORS 82.010(2)(b) expressly makes judgment interest simple unless a contract provides otherwise. Subsection (1)(a) does not state a compounding rule for interest accruing before judgment; the cited federal order used simple interest in its case.

Can I get prejudgment interest against the State of Oregon or an Oregon county? Generally the state and counties have interest immunity. The general interest statute alone does not waive it, but a specific act or lawful contract may supply consent. Cities are treated differently under the cited cases.

Statutes and sources

• ORS 82.010(1)(a), "The rate of interest for the following transactions, if the parties have not otherwise agreed to a rate of interest, is nine percent per annum and is payable on: (a) All moneys after they become due." Accessed 2026-10-06: https://www.oregonlegislature.gov/bills_laws/ors/ors082.html
• ORS 82.010(2)(f), sets the lesser 5%-or-prime-plus-3% POSTjudgment rate for medical-malpractice judgments. Accessed 2026-10-06: https://www.oregonlegislature.gov/bills_laws/ors/ors082.html
• Strader v. Grange Mutual Ins. Co., 179 Or. App. 329, 338 (2002), "a trial court may award prejudgment interest on damages only when the exact amount is ascertained or easily ascertainable." Accessed 2026-07-05: https://law.justia.com/cases/oregon/court-of-appeals/2002/a110669.html
• Spaid v. 4-R Equipment, LLC, 252 Or. App. 46 (2012), collects and applies the ascertainability test from Krieg v. Union Pac. Land Resources Corp. (1974) and Goodyear Tire & Rubber Co. v. Tualatin Tire & Auto (1994). Accessed 2026-07-05: https://caselaw.findlaw.com/court/or-court-of-appeals/1611777.html
• Newport Church of the Nazarene v. Hensley, 335 Or. 1, 17 (2002), holds the state generally retains interest immunity unless a specific statute or lawful agreement supplies consent. Accessed 2026-07-05: https://www.courtlistener.com/opinion/835997/
• Young v. State of Oregon, 346 Or. 507, 515 (2009), reaffirms that ORS 82.010(1)(a) itself is not that authorization. Accessed 2026-07-05: https://www.courtlistener.com/opinion/835163/
• Avenue 33, LLC v. Aventurine Capital Group, LLC, No. 3:23-cv-00896-YY (D. Or. Apr. 10, 2024), applies the default 9% statutory rate as simple interest. Accessed 2026-07-05: https://www.govinfo.gov/content/pkg/USCOURTS-ord-3_23-cv-00896/pdf/USCOURTS-ord-3_23-cv-00896-1.pdf