Sole Proprietorship in Arizona: How to Start One

A sole proprietorship is the simplest way to legally run a business in Arizona, mainly because there is nothing to file to create one. If you start doing business under your own name and you're the only owner, you're already a sole proprietor in the eyes of the state. This guide walks through exactly what an Arizona sole proprietor needs to do to operate legally: registering a trade name if you're not using your own name, getting the right tax accounts, and picking up any local licenses your city requires.

This article covers the practical steps for starting a sole proprietorship in Arizona. If you're weighing a sole proprietorship against an LLC, or your situation involves partners, significant liability exposure, or complex tax questions, talk to a licensed Arizona attorney or CPA before you commit to a structure.

What Is a Sole Proprietorship in Arizona?

A sole proprietorship is an unincorporated business owned and run by one person, with no legal separation between the owner and the business. There's no entity to register with the Arizona Corporation Commission, no Articles of Organization, and no annual report. The tradeoff is personal liability: if the business is sued or can't pay its debts, your personal assets, not just business assets, are on the line. That's the main reason many Arizona business owners eventually convert to an LLC, which the Corporation Commission can form for a $50 filing fee.

Income from an Arizona sole proprietorship passes through to your personal return and is taxed at Arizona's flat 2.5 percent individual income tax rate, on top of federal self-employment tax.

What You'll Need Before You Start

• A business name (your own legal name, or a trade name/DBA if you want to operate under something else)
• A Social Security number or federal Employer Identification Number (EIN)
• An Arizona Transaction Privilege Tax (TPT) license, if you'll sell taxable goods or services
• Any city business license your municipality requires (counties issue no general business license)
• Any professional or occupational license your specific trade requires (contracting, cosmetology, food service, and similar fields)
• A separate business bank account (recommended, not legally required)
• General liability or other business insurance, depending on your industry

How to Start a Sole Proprietorship in Arizona: Step by Step

1. Decide on your business name

You can operate under your own legal name with no paperwork at all. If you want to do business under anything else, for example "Desert Bloom Landscaping" instead of your own name, that's a trade name (commonly called a DBA, or "doing business as") and Arizona lets you register it with the Secretary of State.

2. Register your trade name with the Arizona Secretary of State

Trade name registration in Arizona is handled by the Secretary of State's Business Services Division, not the Corporation Commission. It's filed online at azsos.gov/business/tntm. Registration is optional under state law, meaning you can technically operate under a trade name without registering it, but most sole proprietors register anyway because it puts your claim to the name on the public record and makes it easier to open a business bank account. Confirm the current filing fee on the Secretary of State's page before you file, since it isn't published here.

3. Get a federal EIN (optional, but usually worth it)

A sole proprietor with no employees can legally use a Social Security number for tax purposes. Most owners get a free EIN from the IRS anyway, since banks typically want one to open a business account, and it keeps your SSN off business paperwork.

4. Get a Transaction Privilege Tax (TPT) license if you're selling taxable goods or services

Arizona doesn't issue one general statewide business license. What most businesses actually need instead is a TPT license from the Arizona Department of Revenue, which covers retail sales and most other taxable business classifications. It costs $12 per business location and is applied for at azdor.gov/business/transaction-privilege-tax/tpt-license. The combined state TPT rate is 5.6 percent (5.0 percent base plus a 0.6 percent education increment), and your city or county will typically add its own rate on top, so check what your specific location charges.

5. Check your city or county for local licensing

Cities and towns across Arizona, including Phoenix, Tucson, Mesa, Scottsdale, and Chandler, commonly require their own local business or TPT license in addition to the state license. If your work is in a regulated profession such as contracting, cosmetology, real estate, or food service, your industry board will also have separate licensing requirements. Check with your specific city clerk's office and any relevant state licensing board.

6. Open a separate business bank account

Nothing in Arizona law forces a sole proprietor to keep business and personal money separate, but doing so makes bookkeeping and tax time dramatically easier, and it's the account you'll want if you ever apply for a business loan or convert to an LLC later. Bring your EIN (or SSN), your trade name registration if you have one, and identification to the bank.

7. Set up your tax obligations

As a sole proprietor, business income flows onto your personal Arizona tax return and is taxed at the flat 2.5 percent rate, alongside federal income tax and self-employment tax on your net earnings. If you collect TPT from customers, you'll file and remit that separately to the Department of Revenue on the schedule they assign when you register. Many sole proprietors also need to make estimated quarterly payments to both the IRS and Arizona Department of Revenue rather than paying everything at once in April.

8. Consider business insurance

Because a sole proprietorship offers no liability shield, general liability insurance, and in some fields, professional liability or errors and omissions coverage, is worth pricing out even though Arizona doesn't require it for most sole proprietors. Given that your personal assets are exposed, this is one of the areas where a conversation with an insurance agent or attorney is worth the time.

Tips and Common Mistakes to Avoid

• Skipping the trade name registration and then getting stuck at the bank. Some banks will not open a business account under a name that doesn't match your legal name unless you can show a registered trade name. Ask your bank what it requires.
• Assuming a TPT license isn't needed because you're small. Business size doesn't exempt you; what matters is whether your activity falls into a taxable classification. Confirm your classification directly with the Department of Revenue rather than guessing.
• Mixing personal and business finances from day one. This is legal for a sole proprietor, but it makes tax prep harder and weakens your records if you're ever audited or need to show business income for a loan.
• Forgetting local licensing because the state didn't require one. Arizona's lack of a general state business license doesn't mean your city has no requirement. Check locally before you assume you're fully covered.
• Not planning for estimated tax payments. Sole proprietors who owe more than a small threshold in tax typically need to pay quarterly, and underpaying can trigger penalties at both the state and federal level.

What to Expect After You Register

Once you've registered a trade name (if applicable) and secured any TPT license or local permits your business needs, you should generally be positioned to operate legally as an Arizona sole proprietor. Processing for a Secretary of State trade name filing and a Department of Revenue TPT license timelines vary, so confirm current processing times on each agency's site when you file. Keep in mind that requirements can differ by city, county, and industry, so what's sufficient for one business may not be sufficient for another operating a different type of activity in a different location.

Sole Proprietorship vs. LLC in Arizona

A sole proprietorship costs nothing to form and requires no state filing, but it leaves your personal assets exposed to business debts and lawsuits. An Arizona LLC costs $50 to file (Articles of Organization with the Corporation Commission), has no annual report requirement and no franchise tax, and separates your personal liability from the business in most circumstances. Many sole proprietors start with no formal structure to test a business idea, then convert to an LLC once revenue or risk grows. If you're unsure which fits your situation, that's a good question to bring to a CPA or business attorney rather than deciding on cost alone.

This article is for general informational purposes only and does not constitute legal or tax advice. Requirements can change, and city or county rules vary across Arizona. Consult a licensed Arizona attorney or CPA about your specific situation before making formation, licensing, or tax decisions.