How to Become an Independent Contractor in Washington State

To become an independent contractor in Washington State, you register your business with the Department of Revenue, receive a Unified Business Identifier (UBI) number, choose a legal structure, and take on the tax and insurance responsibilities an employer would normally handle. Registration costs $50 and can be done online through My DOR. But paperwork alone doesn’t make you an independent contractor under Washington law: the state applies strict classification tests, and if the working relationship doesn’t meet them, you can be reclassified as an employee no matter what your contract says.

Register With the Department of Revenue

Washington uses a single application to register you with multiple state agencies at once. You need to register with the Department of Revenue and get a business license if any of the following apply:

Your annual gross income is $12,000 or more.
You collect sales tax.
You do business under a name other than your full legal name.

The application fee is $50 for a new business. Registering a trade name (doing business as) adds $5.¹²

When your application is approved, you receive a nine-digit UBI number. That number is your business identity across every Washington agency, and you’ll use it whenever you file taxes or update your registration. Get it early. As you’ll see below, having a registered account with the Department of Revenue is one of the boxes the state checks when deciding whether you actually qualify as an independent contractor.

Before you apply, gather:

Your business name and chosen structure.
A North American Industry Classification System (NAICS) code describing your work.
A federal Employer Identification Number (EIN) from the IRS if you formed an LLC or plan to hire employees.³

The fastest way to apply is through the Department of Revenue’s My DOR online portal, which requires a free Secure Access Washington (SAW) account.⁴ Paper applications are also accepted. Online applications typically take about ten business days to process; city or state endorsements can add time. The state’s Business Licensing Wizard will flag any city or county licenses your specific work requires.

Choose a Business Structure

Sole proprietorship and limited liability company are the two structures most independent contractors choose between. The choice affects your personal liability, tax treatment, and paperwork.

Sole Proprietorship

A sole proprietorship exists the moment you start doing business. No formation paperwork, no filing fee, no separate tax return. Business income flows straight to your personal return. The trade-off is that you and the business are legally the same. If a client sues or a debt goes unpaid, your personal savings, home, and other assets are exposed.

Limited Liability Company

An LLC creates a separate legal entity that shields your personal assets from business debts and lawsuits, as long as you keep business and personal finances properly separated. Forming an LLC in Washington means filing a Certificate of Formation with the Secretary of State and paying a $180 filing fee.⁵ You’ll also file an annual report ($70) by the last day of the month in which you originally formed the LLC.⁶

S Corporation Tax Election

Once you have an LLC, you can elect S corporation tax treatment by filing IRS Form 2553. Your legal structure doesn’t change, but the way you pay yourself does. You pay yourself a reasonable salary (subject to payroll taxes) and take remaining profits as distributions that aren’t subject to the 15.3% self-employment tax. The election is due no more than two months and 15 days after the beginning of the tax year you want it to take effect. It generally only pays off once your net income is high enough that the tax savings outweigh the added cost of running payroll and filing a corporate return.

Meet Washington’s Classification Tests

Washington presumes you’re an employee unless proven otherwise, and the burden of proof falls on the business paying you. You can register, print business cards, and sign a contract that says “independent contractor” in bold, and the state can still reclassify the relationship. Several of the factors the state examines require you to already be set up as a business before you start working, which is why registration and books belong at the front of the process, not the end.

The ABC Test for Unemployment Insurance

For unemployment insurance under RCW 50.04.140, all three of the following must be true:

You are free from the hiring party’s control or direction over how you perform your work, both in the contract and in practice.
Your services are either outside the client’s usual line of business or performed outside all of the client’s business locations.
You are customarily engaged in an independently established trade, occupation, or business of the same type as the work you’re performing.

Fail any one prong and Washington treats you as an employee for unemployment tax purposes, regardless of what your contract says.⁷

The Six-Part Test for Workers’ Compensation

The Department of Labor & Industries applies a separate, more detailed test under RCW 51.08.195 for workers’ compensation coverage. All six must be satisfied:

You are free from the hiring party’s control or direction over the work.
The work is outside the client’s usual business, performed away from their locations, or you pay for your own principal place of business.
You are engaged in an independently established business of the same type, or you have a principal place of business that qualifies for a federal tax deduction.
You are responsible for filing a schedule of expenses with the IRS.
You have registered with the Department of Revenue and received a UBI number.
You maintain separate books and records for all business income and expenses.

Construction workers face a seventh requirement: a valid contractor registration or electrical contractor license.⁸⁹

Federal classification runs on a different track. The IRS weighs behavioral control, financial control, and the type of relationship, with no single factor deciding the outcome.¹⁰ Meeting Washington’s tests doesn’t automatically satisfy the IRS, and vice versa.

Handle Your Own Federal Taxes

No employer withholds taxes from your payments, so you calculate, set aside, and remit taxes yourself. Missing payments or underestimating triggers penalties that compound quarterly.

Self-Employment Tax

Self-employment tax covers Social Security and Medicare. The combined rate is 15.3%: 12.4% for Social Security on net earnings up to $184,500 in 2026, and 2.9% for Medicare on all net earnings with no cap.¹¹¹² The tax applies to 92.35% of your net self-employment income, and you deduct half of what you pay when calculating your adjusted gross income.

Quarterly Estimated Payments

You’ll make estimated tax payments four times a year to cover both income tax and self-employment tax. The 2026 due dates:¹³

April 15, 2026, for January through March.
June 15, 2026, for April and May.
September 15, 2026, for June through August.
January 15, 2027, for September through December.

To avoid underpayment penalties, pay at least 90% of your current year’s tax liability or 100% of what you owed the previous year (110% if your AGI exceeded $150,000). If you owe less than $1,000 after credits or withholding, you won’t face a penalty regardless.

Deductions to Track

You can deduct ordinary and necessary business expenses, which directly reduces your taxable income. Common ones include health insurance premiums (100% deductible if you have net self-employment income and aren’t eligible for coverage through a spouse’s employer), a home office used exclusively for business, vehicle expenses for business travel, equipment and software, professional development, and business insurance. Track expenses as you go rather than at tax time. IRS Publication 334 covers deductible business expenses; Publication 587 covers the home office deduction.¹⁴

Pay the Washington B&O Tax

Washington has no state personal income tax. It does have a Business and Occupations tax, and this one catches new contractors off guard because it’s a gross receipts tax: it applies to your total business revenue with no deductions for expenses or costs. Even a losing year still owes B&O tax on every dollar received.¹⁵ For most service-based contractors, the rates as of January 1, 2026:¹⁶

1.5% on gross income if your prior-year revenue was under $1 million.
1.75% if prior-year revenue was between $1 million and $4,999,999.
2.1% if prior-year revenue was $5 million or more.

Retailing, wholesaling, and manufacturing have different rates. Your NAICS code and the nature of your work determine which classification applies.

If you’re just starting out or your revenue is modest, the small business B&O tax credit can meaningfully reduce what you owe. For businesses reporting at least 50% of taxable income under the service and other activities classification, the maximum credit is $160 per month, or $1,920 annually for annual filers. The credit phases out as income rises and cannot reduce your B&O liability below zero.¹⁷ At lower income levels, this credit can wipe out your B&O tax entirely.

The Department of Revenue assigns you a filing frequency (monthly, quarterly, or annually) based on your estimated tax liability.

Cover Yourself: Insurance and Optional State Programs

You won’t get employer-sponsored insurance or benefits, so building your own safety net matters.

Business Insurance

General liability insurance covers claims of property damage or bodily injury arising from your work. Errors and omissions insurance (also called professional liability) covers claims based on professional mistakes, missed deadlines, or failure to deliver what you promised. General liability won’t cover those claims. Consultants, designers, bookkeepers, IT professionals, and similar service providers often need both.

WA Cares Fund

Washington’s WA Cares Fund provides long-term care benefits funded through payroll premiums. As a self-employed person, you aren’t required to participate, but you can opt in. The premium rate is 0.58% of your net self-employment earnings.¹⁸ Once you elect coverage, you generally cannot opt back out, so weigh this carefully.

Paid Family and Medical Leave

Washington’s Paid Family and Medical Leave program is also opt-in for self-employed workers.¹⁹ It provides partial wage replacement for a serious health condition, bonding with a new child, or certain military-connected situations. Premiums are quarterly and based on your earnings.

Set Up Retirement

Without an employer plan, you set up your own. Contribution limits for self-employed plans are often higher than a traditional 401(k) offers.

SEP IRA: up to 25% of your net self-employment earnings, capped at $72,000 in 2026. Simple setup, deductible contributions, minimal filing requirements until balances get large.²⁰
Solo 401(k): up to $24,500 as employee deferrals plus employer profit-sharing contributions, combined maximum $72,000 in 2026. Catch-up contributions apply at age 50. Roth contributions are allowed; SEP IRAs don’t allow them.
SIMPLE IRA: up to $17,000 in employee contributions for 2026, with a $4,000 catch-up at 50 and older, or $5,250 if you’re 60 to 63. Lower limits, easier administration if you eventually hire.

Operational Basics That Protect Your Status

Open a separate business bank account immediately. Mixing business and personal funds makes tax reporting harder and, if you formed an LLC, can weaken the liability protection you paid $180 to create. Courts can pierce the veil of an LLC that doesn’t maintain proper separation between owner and entity.

Use a written contract with every client. A solid contract defines scope, timelines, payment terms, and states explicitly that you’re performing the work as an independent contractor. That last point isn’t formality; it’s one of the factors Washington weighs when evaluating classification. If a dispute arises, a well-drafted contract is your first line of evidence.

Keep separate books and records for every dollar of income and every business expense. Washington’s six-part classification test specifically requires it, and the IRS expects it for your Schedule C. Accounting software or a dedicated spreadsheet works. Reconstructing a year’s worth of transactions from bank statements at tax time is how deductions get missed and audits get painful.

1
Washington Department of Revenue. Variable Business License Processing Fees
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Washington Department of Revenue. Apply for a Business License
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Internal Revenue Service. Employer Identification Number
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Washington Department of Revenue. My DOR Set Up
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Washington Secretary of State. Certificate of Formation for Limited Liability Company
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Washington Secretary of State. File an Annual Report (Multiple Entity Types) Online
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Washington State Legislature. Washington Code RCW 50.04.140 – Employment Exception Tests
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Washington State Legislature. Washington Code RCW 51.08.195 – Employer and Worker Additional Exception
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Washington State Department of Labor & Industries. Independent Contractors
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Internal Revenue Service. Independent Contractor (Self-Employed) or Employee?
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Internal Revenue Service. Topic No. 554, Self-Employment Tax
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Social Security Administration. Contribution and Benefit Base
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Internal Revenue Service. Estimated Tax
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Internal Revenue Service. Guide to Business Expense Resources
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Washington Department of Revenue. Business and Occupation Tax
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Washington Department of Revenue. Service and Other Activities Rate Changes
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Washington Administrative Code. Washington Administrative Code 458-20-104 – Small Business Tax Relief Based on Income
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WA Cares Fund. Self-Employed Opt-In
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Washington Paid Family and Medical Leave. Self-Employed
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Internal Revenue Service. SEP Contribution Limits (Including Grandfathered SARSEPs)