Washington Workers' Comp Rate Calculator

Workers' comp in Washington: what's different

Washington runs a monopolistic system with two twists. Coverage comes only from the Washington State Fund, run by the Department of Labor & Industries (L&I), or from an employer certified by L&I to self-insure. Premiums are not a percentage of payroll. L&I charges a rate for each hour worked, and workers pay part of it through payroll deductions. L&I also sets the rates and calculates each employer's experience factor.

Who must carry coverage

Coverage is mandatory for any worker who does not fit an exemption, and there is no minimum number of employees. RCW 51.12.020 lists the only employments left out. Common exclusions:

• Owners. Sole proprietors and partners. Corporate officers are excluded only if they are bona fide officers who are also directors and shareholders, exercise substantial control over daily management, and do not mainly do manual labor. A corporation that is not a public company may instead exempt up to eight shareholder officers regardless of manual labor, or any number of officers related by blood or marriage. LLC members qualify when they would meet the partner or officer test.
• Household work. A domestic worker in a private home, unless two or more are employed regularly for 40 or more hours a week. Gardening and repair work at the employer's own home is also excluded.
• Family farms. A child under 18 working for a parent in farm work.
• Others. Booth renters, insurance producers, newspaper carriers, and some musicians and entertainers hired for specific engagements.

Many excluded people can buy elective coverage. Minors are covered, even in a parent's business, except on a family farm.

Contractors and subcontractors. Construction contractors must pass a seven-part independent contractor test, including a valid contractor registration. The business that lets a contract is primarily responsible for premiums on that work. A registered or licensed contractor escapes that liability only when the subcontractor meets every condition in RCW 51.12.070(1). L&I tells prime contractors to check each subcontractor's certificate of coverage at hiring and every year.

Where coverage comes from

RCW 51.14.010 gives employers two options: insure with the state fund, or qualify as a self-insurer. L&I's guide says the fund gets its money only from premiums paid by employers and employees, not from general tax revenue.

Self-insurance is for large businesses. L&I's guide says companies with at least $25 million in assets, and some government bodies, may qualify. Applicants must show the financial ability to pay all compensation, an accident prevention record, and a claims-handling setup. A self-insured employer pays benefits from company funds and manages its own claims under L&I oversight.

How L&I sets rates

By law, L&I classifies work by hazard and sets basic rates at "the lowest necessary" to keep the accident and medical aid funds solvent. Rates change each January 1. The hourly rate has four parts:

• Accident fund: wage replacement and disability awards. Employers pay all of it.
• Medical aid fund: medical care and vocational services.
• Stay at Work: incentives for light-duty jobs during recovery.
• Supplemental pension fund: cost-of-living adjustments for long-term benefit recipients.

Workers and employers split the last three equally. For 2026, L&I raised the average rate 4.9%, adding about $1.37 a week per full-time position. L&I approved that increase after three public hearings in late October 2025.

For 2027, L&I has proposed another 4.9% average increase, about $1.44 a week per full-time employee. Hearings are set for October 27 to 29, 2026, with final rates due November 30 and effective January 1, 2027. L&I says 311 of its 326 risk classes would see higher base rates. Until the November decision, treat 2027 figures as proposed.

Workers pay part of the premium

Washington is the only state where workers pay a significant share, according to L&I. On average, workers carry about 24% to 25% and employers about 75%. Employers collect the worker share through payroll deductions. Your rate notice shows the most you may withhold per hour for each class, and withholding more is illegal. L&I's guide notes that some employers skip the deduction; they still owe the full premium.

Experience rating

L&I calculates an experience factor for every business each year. There is no premium threshold. Any firm that reported worker hours in the experience period is rated. New businesses start at 1.0000 until they become experience rated.

The experience period is the oldest three of the four fiscal years before the rate year. For 2026, that is July 1, 2021 through June 30, 2024. A claim affects your rates for three years. A factor generally cannot change more than 25% in a year. Firms with no compensable claims in the period get a claim-free discount from 10% to 40%, depending on size.

The factor multiplies the accident, medical aid and Stay at Work rates. L&I then adds the supplemental pension assessment, which is not experience rated.

No assigned risk plan

L&I says it does not use an assigned risk plan. Every employer that is not self-insured buys from the state fund.

Penalties for going uninsured

• Claim costs. If a worker is hurt before you secure coverage, you can be charged 50% to 100% of the cost of the claim.
• Premium penalty. Up to the greater of $1,000 or double the premiums owed for the uninsured period. Penalties in RCW 51.48 are adjusted for inflation every three years starting July 1, 2023, so current amounts can be higher.
• Stop work orders. Registered or licensed contractors without coverage can be ordered to stop work, with a $1,000 penalty for each day of violation.
• Crimes. Doing business without a certificate of coverage is a gross misdemeanor. Doing so after L&I revokes your certificate is a class C felony, as is knowingly failing to secure coverage to evade premiums.

Your ongoing obligations

• Quarterly reports. File and pay by April 30, July 31, October 31 and January 31. Premium is figured on hours, and each overtime hour counts as one hour. Sick leave, vacation and holiday hours are not reported. File even with zero hours. Late accounts face penalties from 5% to 20% of premium, plus 1% interest a month.
• Posting. Post your certificate of coverage at each business location, plus three required L&I posters.
• Serious injuries. Report a work-related death or inpatient hospitalization to L&I within 8 hours, and a non-hospitalized amputation or loss of an eye within 24 hours.

Worked example: how the calculator estimates premium

Premium = hours worked x hourly rate Hourly rate = (accident + medical aid + Stay at Work rates) x experience factor + supplemental pension rate

Roofing is class 0507, Roof Work - Construction and Repair (WAC 296-17A-0507). L&I's 2026 base rates for 0507, per hour worked:

• Accident fund $3.7862, medical aid $1.7600, Stay at Work $0.0556, supplemental pension $0.1912
• Composite at a factor of 1.0000: $5.7930 per hour (down from $5.8440 in 2025)

Hypothetical crew: five roofers working 500 hours each per quarter, or 10,000 hours a year. Hypothetical experience factor: 0.90.

Step 1. Rated portion: $3.7862 + $1.7600 + $0.0556 = $5.6018. Step 2. Apply the factor: $5.6018 x 0.90 = $5.04162. Step 3. Add supplemental pension: $5.04162 + $0.1912 = $5.23282 per hour. Step 4. Annual premium: 10,000 x $5.23282 = $52,328.20 (about $13,082.05 a quarter).

Worker share: workers pay half of the medical aid, Stay at Work and pension parts. At a factor of 1.0000, L&I lists the 0507 maximum deduction as $1.0034 an hour. At 0.90, half of ($1.8156 x 0.90 + $0.1912) is $0.91262 an hour, or $9,126.20 for the crew. The employer pays the other $43,202.00.

The proposed 2027 composite for 0507 is $6.0407, up 4.3%. Wages never enter the formula.

Frequently asked questions

Official sources

• L&I, Rates for Workers' Compensation
• L&I, 2026 Rates by Business Type and Classification Code (PDF)
• L&I, 2026 Hourly Rates by Risk Classification Code and Fund (PDF)
• L&I, Proposed and Indicated 2027 Base Rates (PDF)
• L&I, Proposed 2027 Hourly Rates by Classification Code and Fund (PDF)
• L&I, Proposed Rates (rates notice)
• L&I news release 25-32 (2026 rates)
• L&I news release 26-15 (proposed 2027 rates)
• L&I, Experience Rating
• L&I, Unique Premium Rating Features in Washington
• L&I, Employers' Guide to Workers' Compensation Insurance in Washington State (F101-002-000)
• L&I, Self-Insurance
• RCW 51.12 (coverage and exclusions)
• RCW 51.14 (self-insurers)
• RCW 51.16 (premiums, quarterly reports, worker deductions)
• RCW 51.32.073 (supplemental pension contributions)
• RCW 51.48 (penalties)
• WAC 296-17A-0507 (roof work classification)

Sources accessed 2026-10-17.

This is general information, not legal advice. Confirm details with the Washington State Department of Labor & Industries.

Reviewer: Sam Newland, CFP, Founder of Benefitra. Last updated October 17, 2026. How the calculator works. Editorial policy.