Side Hustle Taxes in Arizona: Self-Employment Tax, State Income Tax, and TPT Explained

Quick answer

If you earn money from a side hustle in Arizona, you may deal with up to four kinds of tax:

1. Federal income tax on your side hustle profit, reported on Schedule C.
2. Federal self-employment (SE) tax for Social Security and Medicare, generally if your net self-employment earnings are $400 or more.
3. Arizona state income tax, a flat rate on Arizona taxable income: 2.5% for tax year 2025 (ADOR). Confirm the tax year 2026 rate with ADOR before you file.
4. Arizona Transaction Privilege Tax (TPT), but only if you sell taxable goods or services (such as retail sales or short-term rentals). Many service side hustles don't owe TPT.

If you'll owe a meaningful amount, you may need to pay quarterly estimated taxes instead of waiting until April. A common rule of thumb is to set aside 25–30% of side hustle profit, but your number depends on your other income. Use it as a starting point, not a promise.

First: all side hustle income counts

A common myth is that you only owe tax if you get a 1099 form. That's not how it works.

• All income is reportable, whether it's paid in cash, by Venmo or Zelle, through an app, or by check, and whether or not you receive a form.
• Form 1099-NEC is what clients typically send if they paid you above the reporting threshold. For payments made in 2026, the threshold is $2,000 (it was $600 for many years). It's scheduled to be inflation-adjusted starting in 2027. (IRS Instructions for Forms 1099-MISC and 1099-NEC; checked October 7, 2026.)
• Form 1099-K comes from payment apps and online marketplaces (third-party settlement organizations). They generally have to send one only if your payments are over $20,000 and over 200 transactions in the year. Payment-card transactions (for example, a card reader) are reportable regardless of amount. (IRS FAQs on the Form 1099-K threshold under the One Big Beautiful Bill; checked October 7, 2026.)

Forms are just reporting. Under these higher thresholds, many side hustlers won't get a form at all, and that changes nothing: your obligation to report income exists either way. The IRS Gig Economy Tax Center is a good plain-English starting point: https://www.irs.gov/businesses/gig-economy-tax-center

Federal: income tax and self-employment tax

Schedule C: your side hustle profit

As a sole proprietor, or a single-member LLC with default tax treatment, you report business income and expenses on Schedule C (Form 1040). Your net profit, meaning income minus allowable business expenses, is what gets taxed.

Common side hustle expenses (if they're ordinary and necessary for your business):

• Supplies and materials
• Business mileage or actual vehicle costs (delivery, pet sitting, cleaning, photography shoots). See the 2026 mileage rates below.
• Platform and payment processing fees
• Software and subscriptions used for the business
• A portion of your phone and internet, if used for business
• Home office, if you meet the IRS requirements (regular and exclusive use)
• Licenses and fees, including Arizona TPT license fees and ACC filing fees

Schedule C: https://www.irs.gov/forms-pubs/about-schedule-c-form-1040

Self-employment tax

When you work for an employer, they withhold Social Security and Medicare and pay a matching share. When you're self-employed, you pay both halves. That's self-employment tax.

• Rate: 15.3% total (12.4% Social Security + 2.9% Medicare).
• Applied to: 92.35% of your net self-employment earnings.
• Social Security cap: The 12.4% portion only applies up to the annual Social Security wage base, which is $184,500 for 2026 (SSA). Your W-2 wages count toward that cap first.
• Additional Medicare Tax: An extra 0.9% applies to wages and self-employment income above $200,000 (single, head of household, and other filers), $250,000 (married filing jointly), or $125,000 (married filing separately). (IRS Topic 560.)
• Filing trigger: generally owed if net SE earnings are $400 or more.
• Deduction: You can generally deduct half of your SE tax when figuring your adjusted gross income.

(SE rate, 92.35% base, and $400 trigger: IRS Topic 554; wage base: SSA Contribution and Benefit Base; all checked October 7, 2026.)

Simple illustration (not a prediction): If your side hustle nets $10,000 profit for the year, SE tax is roughly $10,000 × 92.35% × 15.3% ≈ $1,413, before federal and Arizona income tax on that profit. Your actual total depends on your tax bracket, deductions, and other income.

Schedule SE: https://www.irs.gov/forms-pubs/about-schedule-se-form-1040

Qualified business income (QBI) deduction

Many sole proprietors can deduct up to 20% of qualified business income under Section 199A, subject to limits. The deduction has been made permanent. Starting in 2026, there's also a minimum deduction of $400 if you have at least $1,000 of qualified business income from an active trade or business. The income range where limits phase in is $75,000 ($150,000 married filing jointly). (IRS 2026 Form 1040-ES, "What's new"; checked October 7, 2026.) Tax software or a preparer will usually calculate this for you.

2026 standard mileage rates

If you use the standard mileage rate for business driving, the IRS set two rates for 2026:

(IRS, Standard mileage rates, page updated July 28, 2026; checked October 7, 2026.) Because the rate changes mid-year, your mileage log needs dates, not just a yearly total.

Quarterly estimated taxes

The U.S. tax system is pay-as-you-go. Side hustle income has no withholding, so the IRS expects you to pay during the year through estimated tax payments if you expect to owe enough.

General federal rule: You generally need to make estimated payments if you expect to owe $1,000 or more in federal tax for the year after subtracting withholding and refundable credits. (IRS, Estimated taxes; 2026 Form 1040-ES.)

Typical federal due dates (if a date falls on a weekend or holiday, it moves to the next business day). These follow the IRS's standard schedule; confirm each year's dates on the current Form 1040-ES before you pay:

How to avoid an underpayment penalty ("safe harbor"): In general, you avoid the penalty if your withholding plus estimated payments cover at least the smaller of 90% of this year's tax or 100% of last year's tax. If last year's AGI was above $150,000 ($75,000 if married filing separately), the prior-year figure is 110%. (2026 Form 1040-ES.)

Uneven income? If most of your profit lands in one part of the year, the IRS annualized installment method (Form 2210) can lower or eliminate penalties for the slow quarters.

The easier option if you have a W-2 job: Increase your withholding at work by submitting a new Form W-4 to cover side hustle tax. Withholding counts as paid evenly through the year, which can be simpler than tracking quarterly deadlines.

How to pay: IRS Direct Pay (https://www.irs.gov/payments/direct-pay), your IRS Online Account, or EFTPS. Form 1040-ES has the worksheet: https://www.irs.gov/forms-pubs/about-form-1040-es

Arizona state income tax

Arizona has a flat individual income tax rate. It is 2.5% for tax year 2025, per the Arizona Department of Revenue. Confirm the tax year 2026 rate with ADOR before you file. Your side hustle profit flows into your Arizona return (Form 140 for most full-year residents) through your federal adjusted gross income.

What this means for side hustlers:

• No brackets to think about at the state level. For tax year 2025, roughly 2.5% of each additional dollar of Arizona taxable income goes to state income tax.
• Arizona doesn't have a separate state self-employment tax.

Arizona estimated payments (Form 140ES): You're required to make Arizona estimated payments if your Arizona gross income was more than $75,000 (single, head of household, or married filing separately) or more than $150,000 (married filing jointly) in both the prior year and the current year. For 2026, that means both 2025 and 2026. (ADOR 2026 Form 140ES instructions; checked October 7, 2026.) Confirm the Arizona due dates in the Form 140ES instructions before you pay. Below those thresholds, payments are optional, and many side hustlers with a W-2 job handle the Arizona share by adjusting their Arizona withholding election (Form A-4) with their employer.

Part-year residents and snowbirds: If you moved to Arizona during the year or split time between states, your filing is more complicated (part-year or nonresident returns, and possibly returns in two states). This is a good time to use a pro.

Arizona Department of Revenue, Individual Income Tax Highlights: https://azdor.gov/forms/individual-income-tax-highlights · 2026 Form 140ES instructions: https://azdor.gov/sites/default/files/document/FORMS_INDIVIDUAL_2026_140iES.pdf

Arizona TPT: the tax most side hustlers get wrong

Arizona doesn't have a traditional "sales tax." It has the Transaction Privilege Tax (TPT), a tax on the privilege of doing certain kinds of business in Arizona. It's charged to the seller, though sellers usually pass it on to customers.

Short version:

• Often needs TPT: selling physical products (retail), short-term rentals, some event and amusement activities, and certain other business classes.
• Often doesn't: many personal and professional services, such as tutoring, freelance writing, consulting, and many cleaning or pet-care services. (Confirm with ADOR for your specific activity.)
• License fee: The state TPT license is $12 per location, plus city license fees that vary by city. (ADOR, TPT License page; checked October 7, 2026.)
• Platforms: Some marketplaces collect and remit TPT for sales made through them under Arizona's marketplace facilitator rules. That can change what you owe for those sales. Confirm how it applies to you with ADOR.
• Registration: through AZTaxes (https://www.aztaxes.gov/). State and most city TPT are handled together through ADOR.

TPT is detailed enough to need its own guide: Arizona TPT License for Side Hustles.

Important: TPT is separate from income tax. If you collect TPT from customers, that money isn't yours. Set it aside in full.

The set-aside checklist

This is a practical system, not tax advice. Adjust the percentages with a tax pro once you know your real numbers.

Every time you get paid:

• Move a fixed percentage of the profit into a separate savings account labeled "Taxes." Common starting points:
  • ~25% if your total income is modest and you have a W-2 job with normal withholding
  • ~30% if your side hustle income is significant or you're in a higher bracket
  • Re-check after your first quarter. If you consistently over-save, lower it. If under, raise it.
• If you collect TPT, move 100% of the TPT collected into the tax account (or a separate TPT account).
• Log the payment in your income tracker (date, payer, amount, platform).

Every month:

• Reconcile business income and expenses (bank, apps, cash).
• Save receipts (photo or PDF) for anything over a few dollars.
• Log business miles with dates if you drive for the hustle (the 2026 rate changes on July 1).
• File and pay TPT if you're on a monthly schedule (ADOR assigns your filing frequency).

Every quarter:

• Estimate year-to-date profit.
• Make federal estimated payment (or confirm withholding covers it).
• Make Arizona estimated payment if required (see the 140ES thresholds above).
• File TPT if you're on a quarterly schedule.

Every January:

• Collect 1099s and compare them to your own records; platforms make mistakes. Don't assume a missing form means missing income.
• Send 1099-NECs to any contractors you paid $2,000 or more for 2026 work (check the threshold each year).
• Pay the Q4 federal estimate by mid-January.
• Decide whether to file yourself or hire a pro.

Recordkeeping that actually holds up

The IRS expects you to be able to back up your income and expenses. Good records also mean you don't miss deductions.

Keep:

• Bank and card statements for your business account
• Platform payout reports (download annual summaries before you lose access)
• Receipts and invoices
• A mileage log: date, start and end location or purpose, and miles. Apps work, and so does a notebook. For 2026, miles driven January–June use 72.5¢ and July–December use 76¢ under the standard mileage rate.
• Copies of your tax returns, 1099s, and estimated payment confirmations

How long: Generally at least three years after filing, and longer in some cases. See IRS recordkeeping guidance: https://www.irs.gov/businesses/small-businesses-self-employed/recordkeeping

Simple setup that works for most side hustles:

1. A separate checking account for the hustle (doesn't have to be an LLC account)
2. A spreadsheet, or bookkeeping software if you have lots of transactions
3. A receipts folder (cloud or physical)
4. A mileage tracker if you drive

Filing: DIY software vs. a pro

Free options first:

• IRS Free File for eligible filers (income limits apply): https://www.irs.gov/filing/irs-free-file-do-your-taxes-for-free
• VITA / TCE free tax help sites for eligible taxpayers. Some sites can't handle more complex self-employment returns, so call ahead: https://www.irs.gov/individuals/free-tax-return-preparation-for-qualifying-taxpayers
• Arizona-specific free filing options may be available; check the Arizona Department of Revenue for the current list before you file.

Paid tax software usually handles Schedule C, Schedule SE, and your Arizona Form 140. Check that the tier you pick includes self-employment income, because the cheapest tiers often don't.

When to get a pro (CPA or enrolled agent):

• Your side hustle profit is large enough that you're wondering about an S-corp election
• You have employees or pay contractors
• You moved to or from Arizona this year, or you earn income in multiple states
• You run a short-term rental (TPT, city rules, depreciation)
• You got an IRS or ADOR notice you don't understand
• You missed estimated payments or prior-year filings
• You just don't want to deal with it, which is a valid reason

To check a preparer's credentials, the IRS has a directory of federal tax return preparers with credentials: https://irs.treasury.gov/rpo/rpo.jsf

Arizona-specific tips

• Summer slowdowns change your quarterly math. If your hustle is seasonal (snowbird pet sitting, winter events, spring training), most of your profit may land in Q1 and Q4. The IRS annualized installment method (Form 2210) means you're not overpaying in slow quarters. Ask your preparer.
• Delivery drivers in the heat: Vehicle wear, extra fuel from running AC, and summer tire replacement are real costs. Choose either the standard mileage rate or actual expenses carefully, because switching later has rules. In 2026, remember the mid-year rate change (72.5¢ then 76¢).
• Don't confuse TPT with income tax. We've seen people assume their TPT filing covers their income tax, or the other way around. They're completely separate.
• Keep your ADOR login safe and current. If you have a TPT license, you'll file on AZTaxes even in periods with zero sales (when required).