You can start a sole proprietorship in Arizona without filing any formation documents with the state. The business and you are the same legal person, so no articles, no charter, no formation fee. The trade-off is direct personal liability for every debt and lawsuit the business takes on. What you do need to handle, before or shortly after you open, is a short list: register a trade name if you’re not using your own, get a federal tax ID, register for Transaction Privilege Tax if your work is taxable, clear any city licensing and zoning rules, and pick up any professional license your field requires.
Register a Trade Name (Only If You Need One)
Operating under your own full legal name requires no name filing at all. The moment you want to do business as anything else, you register a trade name with the Arizona Secretary of State under A.R.S. § 44-1460. The application asks for your legal name, your business address, a description of the business, and how long you’ve been using the name in Arizona.
The fee is $10, and the registration is good for five years from the date the Secretary of State receives it. Filing happens through the Secretary of State’s online system. Paper PDF applications are no longer accepted and will be returned. If you don’t have a credit or debit card, you can mail a check or money order with a copy of your application, but the application itself still has to be submitted online.
Search the Secretary of State’s trade name database before you commit to a name. A duplicate or confusingly similar name can get your filing rejected. You’ll also need the registered name to open a business bank account, since banks won’t process checks or issue cards in a business name that isn’t tied to you through an official filing.
Get an Employer Identification Number
An EIN is a free nine-digit federal tax ID from the IRS. Apply through the IRS website and the online application issues the number right away. A sole proprietor with no employees can technically use a Social Security number for tax purposes, but an EIN keeps your SSN off invoices, bank forms, and vendor paperwork, which cuts your identity-theft exposure. You’ll also need one before you can hire anyone or open certain business accounts.
Register for Transaction Privilege Tax
Arizona’s Transaction Privilege Tax isn’t a traditional sales tax. It’s a tax on the privilege of doing business in the state, and the business owes it even if you pass the cost to customers. If any of your activity is taxable, register for a TPT license through AZTaxes.gov by filing the Joint Tax Application (Form JT-1). The base fee is $12 per location, and the total runs up to $50 depending on the municipality.
Your filing frequency depends on expected annual TPT liability:
- Less than $2,000: file annually.
- $2,000 to $8,000: file quarterly.
- Above $8,000: file monthly.
Seasonal businesses that operate eight months or fewer can apply for a seasonal schedule.
City Licensing, Zoning, and Professional Licenses
State registration is one layer. Arizona cities run their own business licensing, and the requirements depend on where you operate and what you do. Call your city’s licensing or finance department before you open.
If you plan to work from home, zoning matters. A.R.S. § 9-462.01 gives municipalities broad authority over land use, including whether a residential property can host a commercial operation. Many cities require a home occupation permit before you can see clients at the house, store inventory above a certain amount, or post signage. Violating a local zoning ordinance can bring fines and a cease-operations order.
Some industries need a license from a dedicated state board before you can legally practice. Contractors, cosmetologists, real estate agents, and healthcare providers all fall into this category. Operating without the required professional license is a class 1 misdemeanor in Arizona, carrying up to six months in jail.
Open a Business Bank Account
Mixing personal and business funds is one of the most common early mistakes. A dedicated business account keeps records clean and makes tax time far easier. Banks usually ask for your EIN or SSN, your trade name registration certificate if you’re using a business name, and a government-issued photo ID. Some will also want a copy of your city business license.
Plan for Taxes From Day One
Sole proprietorship income flows straight to your personal return. You report profits and losses on Schedule C with your Form 1040. There is no separate business return.
On top of regular income tax, you owe self-employment tax to cover Social Security and Medicare at a combined 15.3% of net earnings. The Social Security portion applies to the first $184,500 of earnings in 2026; the Medicare portion has no cap. An additional 0.9% Medicare surtax kicks in once earnings pass $200,000, or $250,000 if married filing jointly. You can deduct half of your self-employment tax when figuring adjusted gross income.
Because no employer is withholding, you make quarterly estimated payments to the IRS using Form 1040-ES. For the 2026 tax year the due dates are April 15, June 15, September 15, and January 15, 2027. Miss them and you’ll owe penalties and interest even if you pay the full balance at filing.
Arizona imposes a flat 2.5% individual income tax, and your business income flows through the same way it does federally. The Arizona Department of Revenue offers a small business income election that may let qualifying taxpayers have small business gross income taxed separately. Ask ADOR or a tax professional whether the election fits your situation.
Buy the Insurance a Sole Proprietor Actually Needs
A sole proprietorship gives you zero liability protection, so insurance is how you put a buffer between the business and your personal assets. General liability covers bodily injury, property damage, and related suits. If you sell a product, product liability covers claims that something you sold caused harm. If you provide a service, professional liability covers errors, negligence, and malpractice claims.
Home-based owners often assume their homeowner’s policy covers business activity. Most policies explicitly exclude it. You can usually add a rider for a limited amount of business equipment and third-party injury coverage. A business owner’s policy bundles general liability and commercial property into one package and is usually cheaper than buying each piece separately.
If You Plan to Hire
The day you bring on an employee, your obligations multiply. Arizona’s minimum wage is $15.15 per hour as of January 1, 2026, well above the federal $7.25. You have to verify every new hire’s identity and work authorization on Form I-9 and keep that form for three years after hire or one year after separation, whichever is later.
You withhold federal income tax, Social Security, and Medicare from each paycheck and report those amounts quarterly on Form 941. You also owe federal unemployment tax (FUTA) at 6.0% on the first $7,000 of each employee’s wages, with a credit of up to 5.4% if you pay your state unemployment contributions on time, bringing the effective rate down to 0.6%.
Arizona requires workers’ compensation coverage for all employees. A sole proprietor with no employees doesn’t have to carry workers’ comp on themselves but may elect to. The moment you hire your first worker, coverage becomes mandatory.
Keep Records From the First Transaction
Keep a separate record of every business transaction from day one: income received, expenses paid, mileage logs, receipts for purchases above a nominal amount, and copies of every filed tax return. The IRS generally wants records supporting income, deductions, and credits for at least three years from the date you file; underreport income by more than 25% and that stretches to six. Employment tax records should be kept at least four years after the tax is due or paid. Digital bookkeeping software handles this far better than a shoebox, and the software itself is a deductible business expense.