Washington Judgment Interest 2026: How RCW 4.56 Rates Are Calculated

Four Rates, One Statute: How RCW 4.56.110 Works

RCW 4.56.110 is Washington's central statute on interest on judgments. It does not publish a single statewide percentage for every case. Instead, it routes judgments into categories — and each category has its own rate rule.

Why Washington uses multiple rates: The legislature treated child-support arrears, consumer debt, public-entity torts, and ordinary civil judgments as different policy problems. Child-support arrears get a high fixed rate to discourage nonpayment. Consumer debt gets a fixed 9% to create predictability. Certain government and student-loan categories track short-term Treasury yields. General judgments are tied to the state's maximum usury-related rate framework under RCW 19.52.020.

How to identify your category before calculating: 1) Read the judgment caption and causes of action. 2) Ask whether the debt is child support, consumer debt as defined in Washington collection statutes, a tort judgment against a governmental entity, a private student-loan judgment, or a general civil money judgment. 3) Only then select the RCW 4.56.110 subsection that matches. 4) Apply that rate to principal × time.

The most common calculator error in Washington: grabbing one "Washington judgment interest rate" from a national chart and applying it to every file. A credit-card judgment at 9% and a child-support arrearage at 12% are not interchangeable. On $20,000 for three years, that 3-point gap is $1,800 in interest alone.

Official orientation points: — Statute text: RCW 4.56.110 (interest on judgments) — Related maximum-rate statute: RCW 19.52.020 — Consumer-debt definition context: RCW 6.01.060 and related collection provisions — Variable-rate publications: Washington Department of Financial Institutions (dfi.wa.gov) and Washington Courts resources (courts.wa.gov)

TheLegalCalc Washington Judgment Interest Calculator at /judgment-interest-calculator/washington is designed for planning estimates once you know which rate bucket applies. This guide explains how to choose the bucket first.

Consumer Debt: 9% Fixed Rate

For consumer debt judgments, Washington uses a fixed 9% per year under RCW 4.56.110(5). This rate does not float with Treasury bills. It stays at 9% regardless of whether short-term yields are rising or falling.

What typically counts as consumer debt in this lane: Credit cards, many personal loans, medical bills, and similar household obligations that fall within Washington's consumer-debt collection definitions (see RCW 6.01.060 and related provisions for the statutory definition used in collection practice). When a judgment arises from that category, the 9% fixed rate is the default interest rule under § 4.56.110(5).

What does not automatically get 9%: Child-support arrears (12%), many government tort judgments (T-bill + 2%), and general civil judgments that use the RCW 19.52.020 maximum-rate framework. Mislabeling a support arrearage as "consumer debt" understates interest by three percentage points every year.

Simple interest formula for a fixed rate: Interest = Principal × 0.09 × Years (or Principal × 0.09 × (Days ÷ 365) for partial years)

Example — consumer debt $30,000 unpaid for 2 years: $30,000 × 0.09 × 2 = $5,400 interest Total with principal: $35,400 (before costs, fees, or credits)

Example — consumer debt $30,000 unpaid for 180 days: $30,000 × 0.09 × (180 ÷ 365) ≈ $1,331.51

Why fixed rates matter for modeling: Creditors and debtors can forecast payoff without checking a quarterly T-bill bulletin. The tradeoff is that 9% can be higher or lower than the variable general rate in any given year — but for consumer judgments, the statute picks predictability over market tracking.

Step-by-step for a consumer judgment: 1) Confirm the judgment is consumer debt under Washington definitions. 2) Use 9% (RCW 4.56.110(5)). 3) Count days or years from the correct start date (generally judgment entry for Washington — see the timing section). 4) Apply simple interest unless a specific order says otherwise. 5) Subtract credits and partial payments from principal before later accrual.

Child Support Arrears: 12% — The Highest

Child support arrears in Washington accrue interest at 12% per year under RCW 4.56.110(2). That is the highest of the four common Washington judgment-interest buckets and one of the highest support-arrears rates in the Pacific region.

Why 12% is so high: Policy makers treat unpaid child support as a priority obligation. A high fixed arrears rate increases the cost of delay and strengthens enforcement leverage. It is not the same rate as consumer credit-card judgments (9%) and should never be swapped.

Regional comparison (planning context, not a substitute for each state's statute): — Washington child-support arrears: 12% (RCW 4.56.110(2)) — California support interest commonly discussed around 10% in many enforcement contexts (verify current California rules) — Oregon often ties certain interest concepts to prime-related benchmarks rather than a flat 12% Washington-style arrears rate

Example — $20,000 child-support arrears unpaid for 3 years at 12%: $20,000 × 0.12 × 3 = $7,200 interest Total with principal: $27,200 (before fees, costs, or credits)

Example — $20,000 arrears for 1 year: $20,000 × 0.12 = $2,400

Daily burn at 12% on $20,000: $20,000 × 0.12 ÷ 365 ≈ $6.58/day

Critical differential: Many parents searching "Washington judgment interest" find a general civil rate and wrongly apply it to support arrears. On $20,000 for three years, using 9% instead of 12% understates interest by $1,800. Using a ~10% California mental model understates Washington by about $1,200 over the same period.

If your case mixes current support and arrears, separate the arrearage principal before applying 12%. Interest on arrears is a calculation problem layered on top of the underlying support order — not a replacement for the monthly support amount itself.

For modeling, use /judgment-interest-calculator/washington after confirming the 12% arrears category applies, and cross-check with Washington Division of Child Support materials when enforcement is active.

Government Tort Judgments: T-Bill Rate + 2%

Certain judgments against governmental entities for tortious conduct use a variable rate: the 26-week U.S. Treasury bill yield plus 2 percentage points, under RCW 4.56.110(3). Private student-loan judgments can follow a similar T-bill + 2% structure under RCW 4.56.110(4).

How the variable rate works: 1) Identify the applicable 26-week T-bill yield for the relevant period. 2) Add 2.00%. 3) Apply that annual rate to the judgment principal for the accrual period.

Where to find the published inputs: Washington Department of Financial Institutions (dfi.wa.gov) publishes interest-rate information used in consumer and usury-related contexts, and Washington Courts (courts.wa.gov) provide judicial resources. Because the T-bill component moves with markets, the government-tort rate is not a forever-fixed percentage like consumer 9% or support 12%.

When it changes: Short-term Treasury yields move continuously; practical legal practice updates the applicable rate when the judgment is entered and as subsequent accrual periods require under the statute and court practice. Always pull the current published figure rather than reusing last year's spreadsheet.

Illustrative example (replace with the live T-bill figure before filing anything): Assume a 26-week T-bill yield of 4.50% for teaching purposes. Government tort rate = 4.50% + 2.00% = 6.50% On a $100,000 judgment for one year: $100,000 × 0.065 = $6,500

If the same judgment were mistakenly calculated at consumer 9%: $100,000 × 0.09 = $9,000 — a $2,500 overstatement caused solely by picking the wrong RCW 4.56.110 bucket.

If it were mistakenly calculated at support 12%: $100,000 × 0.12 = $12,000 — a $5,500 overstatement.

That is why category identification is the first calculation step in Washington, not the third.

General Civil Judgments: Maximum Statutory Rate

General civil money judgments that do not fall into the consumer, child-support, government-tort, or student-loan special rules use the maximum rate framework referenced through RCW 4.56.110 and RCW 19.52.020.

RCW 19.52.020 sets Washington's maximum interest structure for written and unwritten agreements in the usury/maximum-rate sense. Judgment interest for general civil judgments is tied to that maximum-rate concept rather than to the fixed 9% consumer bucket or the 12% support bucket.

How to find the practical rate: Check current Washington DFI publications and court resources for the maximum rate in effect for the relevant period. In recent market conditions, practitioners often discuss general judgment rates in a roughly 9–10% band when short-term yields are elevated — but that band is a description of market-linked maximums, not a substitute for the published figure on the day you calculate.

Difference in practice: — Consumer debt: locked at 9% even if the maximum rate is higher or lower. — Child support arrears: locked at 12%. — Government torts / certain student loans: T-bill + 2% (variable). — General civil: maximum rate under the RCW 19.52.020 framework (variable with the published maximum).

Modeling tip: If you do not yet know the category, do not average the four rates. Run scenario brackets (9%, 12%, T-bill+2%, and current max rate) only as a sensitivity analysis, then replace the bracket with the single correct statutory rate once the judgment type is confirmed.

For 2026 planning articles and calculators, always disclose when a variable rate was last checked. A page that freezes one general rate forever will drift out of date as T-bill yields move — which is exactly the failure mode Washington's multi-rate statute was written to avoid for specialized categories, and that RCW 19.52.020 creates for the general maximum.

Step-by-Step: Calculating Washington Judgment Interest

Use this sequence every time. Skipping step 1 is how Washington calculations go wrong.

Step 1 — Identify the judgment type. Child support arrears → 12% (RCW 4.56.110(2)) Consumer debt → 9% (RCW 4.56.110(5)) Government tort → 26-week T-bill + 2% (RCW 4.56.110(3)) Private student loan (as covered) → 26-week T-bill + 2% (RCW 4.56.110(4)) General civil → maximum rate under RCW 19.52.020 / RCW 4.56.110 framework

Step 2 — Find the correct numeric rate. Fixed categories: use 9% or 12%. Variable categories: pull the current T-bill-based or maximum rate from dfi.wa.gov / courts.wa.gov publications.

Step 3 — Confirm principal. Start with the judgment's unpaid money amount after credits. Include costs or fees only if the judgment and statute treat them as part of the interest-bearing judgment.

Step 4 — Confirm the day count and start date. Washington generally keys judgment interest to the judgment date (entry), which differs from Michigan's frequent complaint-filing start and from Illinois pre-judgment interest rules. Count days from the correct start to the payoff/tender date.

Step 5 — Apply the formula. Interest = Principal × Annual Rate × (Days ÷ 365) Or, for whole years at a fixed rate: Principal × Rate × Years

Worked set: A) Consumer debt $30,000 × 9% × 2 years = $5,400 B) Child support arrears $20,000 × 12% × 3 years = $7,200 C) Government tort $100,000 × (T-bill% + 2%) × 1 year = depends on the live T-bill input D) General civil $100,000 × (current max rate) × 1 year = depends on the published maximum

Step 6 — Sanity-check category risk. If switching the category changes the result by thousands of dollars, you have confirmed why Washington forbids one-rate-fits-all calculators.

Step 7 — Model in the tool. /judgment-interest-calculator/washington

Document the rate source and date checked. Variable-rate judgments need a dated citation to the T-bill or maximum-rate publication used.

When Does Washington Judgment Interest Start?

Washington judgment interest generally begins on the date of the judgment — the entry date — not on the date the complaint was filed. That is a critical contrast with Michigan (often filing-date based under MCL § 600.6013) and with Illinois pre-judgment interest (filing date for covered PI/WD cases under 735 ILCS 5/2-1303).

Why judgment date matters: A Washington case that sits for three years before trial does not automatically pile statutory post-judgment interest during the pre-trial years the way a Michigan filing-date regime might. Prejudgment interest, if any, is a separate substantive question under Washington law and the pleadings — not the same thing as RCW 4.56.110 post-judgment accrual.

Appeals: Interest questions during appeal depend on whether the judgment is stayed, whether a supersedeas bond is posted, and what the appellate orders say. Do not assume accrual stops merely because a notice of appeal was filed.

Partial payments: Credits reduce principal going forward. Keep a ledger: date, amount, principal vs interest allocation if the parties or court specify one.

Practical timeline checklist for Washington: 1) Judgment entry date on the docket 2) Judgment type → correct RCW 4.56.110 rate 3) Any stay or bond affecting enforceability 4) Day count to proposed payoff 5) Recalculation after each partial payment

If you are comparing multi-state judgments in one dispute (for example, a creditor with Michigan and Washington judgments), apply each state's start-date rule separately. Importing Michigan's filing-date habit into a Washington file overstates interest; importing Washington's judgment-date habit into a Michigan file understates it.

DFI, Courts, and the Washington Calculator

Washington judgment interest is a category problem first and an arithmetic problem second.

Official and primary sources: — RCW 4.56.110 (interest on judgments): https://app.leg.wa.gov (search RCW 4.56.110) — RCW 19.52.020 (maximum interest framework) — Washington Department of Financial Institutions rate resources: https://dfi.wa.gov — Washington Courts: https://www.courts.wa.gov

Free planning calculator: /judgment-interest-calculator/washington

How to use this guide with the calculator: 1) Classify the judgment (consumer, support arrears, government tort, student loan, or general civil). 2) Lock the matching rate (9%, 12%, T-bill+2%, or current maximum). 3) Confirm judgment-entry start date and day count. 4) Run the estimate. 5) Verify variable rates on dfi.wa.gov the same day you finalize a demand or payoff letter.

Remember the three differentials that make Washington different from one-rate states: four statutory rate buckets, 12% child-support arrears as the regional high, and judgment-date accrual rather than Michigan-style filing-date accrual for ordinary post-judgment interest.