Washington Prejudgment Interest Rate
United States Washington’s prejudgment interest rate — when a court awards it.
Set by statute Fixed by statute
Washington prejudgment interest is 12% per year, as simple interest under RCW 19.52.010(1). Prejudgment interest is available ONLY on LIQUIDATED or readily-determinable claims — those where the evidence furnishes data that makes it possible to compute the amount with exactness,…
When Washington prejudgment interest applies
Prejudgment interest is available ONLY on LIQUIDATED or readily-determinable claims — those where the evidence furnishes data that makes it possible to compute the amount with exactness, without reliance on opinion or discretion (Prier v. Refrigeration Eng'g; Hansen v. Rothaus). It is BARRED on UNLIQUIDATED claims requiring jury/court discretion or opinion evidence to fix the amount.
When it starts accruing
Prejudgment interest accrues from the date the claim became liquidated / the amount became due and determinable (i.e., the date the liquidated sum could be computed), running until entry of judgment.
Simple or compound
Simple.
→ Compare with the Washington post-judgment interest rate (interest after judgment)
Prejudgment interest under RCW 19.52.010(1) — 12% (simple interest). This is PREjudgment interest (accruing before entry of judgment) and is separate from Washington’s post-judgment rate; availability is limited by claim type (see the page). Verify against the statute text. Not legal advice.
Effective-date history
| Effective date | Rate | Basis |
|---|---|---|
| July 9, 2026 | 12% | Statute |
Source & provenance
Latest value retrieved July 10, 2026 (02:55 UTC) from the official source:
https://app.leg.wa.gov/rcw/default.aspx?cite=19.52.010