Self-employed taxes in Arizona: How to calculate quarterly payments

Working for yourself in Arizona has plenty of benefits, but it also means you’re responsible for paying your own taxes. Unlike traditional employees who have tax withheld automatically, self-employed workers usually need to make quarterly estimated tax payments. Here’s how to know if you need to pay, when to pay, and how to calculate the right amount.

Who Has to Make Quarterly Payments in Arizona?

Arizona requires self-employed individuals, freelancers, and small business owners to make estimated payments if they expect to owe more than $1,000 in state income tax for the year.

The same rule applies at the federal level: if you’ll owe at least $1,000 after subtracting credits and withholding, you’re expected to pay taxes in four installments.

👉 In short: if you’re earning consistent self-employment income, you’ll almost certainly need to file quarterly. For planning beyond taxes, tools like a land loan repayment schedule calculator can help you map out long-term obligations alongside quarterly payments.

Quarterly Due Dates for 2025

Estimated payments are split across the year. For both the IRS and Arizona Department of Revenue, the deadlines are:

• April 15, 2025
• June 17, 2025
• September 16, 2025
• January 15, 2026 (for the final quarter)

Mark these dates—missing them can lead to penalties and interest.

Federal vs. Arizona: What’s the Difference?

Being self-employed means you may owe both federal and state estimated taxes. Here’s how they compare:

Category	Federal (IRS)	Arizona (ADOR)
Form	1040-ES	140ES-SBI
Tax Types	Income tax + 15.3% self-employment (Social Security + Medicare)	State income tax
Threshold	$1,000+ owed	$1,000+ owed
Safe-Harbor	90% of current year or 100% of prior year	Same

How to Calculate Your Quarterly Payments

Step 1: Estimate Your Annual Income

Add up expected earnings from freelancing, contracting, or small business activities. Subtract deductible business expenses.

Step 2: Calculate Federal Tax

Use IRS Form 1040-ES.

• Figure your self-employment tax (15.3% of net profit).
• Add income tax based on federal brackets.

Step 3: Calculate Arizona State Tax

Arizona uses a flat 2.5% income tax rate for 2025.

• Multiply your taxable income by 2.5%.
• Subtract credits or withholdings.

Step 4: Apply Safe-Harbor Rule

Pay 90% of this year’s tax or 100% of last year’s tax, whichever is easier. This protects you from penalties even if your income changes.

Step 5: Divide by Four

Split your total estimated tax into four equal payments—unless your income is uneven, in which case you can adjust payments.

Example: Freelancer in Arizona

Let’s say you expect $60,000 in net self-employment income for 2025.

• Federal self-employment tax: ~$9,180 (15.3% of $60,000)
• Federal income tax: varies, but assume ~$3,500 after deductions
• Arizona state tax: $1,500 (2.5% of $60,000)
• Total: ~$14,180

Quarterly payment: about $3,545 per due date. If you want to see how extra freelance income could accelerate financial goals, try running numbers through a land loan early payoff calculator.

How to Pay in Arizona

• Online: AZTaxes.gov (fastest option)
• By Mail: With Form 140ES voucher and check
• Electronic Funds Transfer (EFT): If preferred, set up recurring payments

Federal payments can be made through the IRS Direct Pay system or EFTPS. To understand how future tax obligations might affect your ability to borrow, you can also explore a land loan rates calculator for perspective on costs.

What If You Don’t Pay Enough?

Underpaying your quarterly taxes can result in interest and penalties, even if you file on time. To avoid this:

• Stick to the safe-harbor rule.
• Recalculate mid-year if your income rises.
• Make catch-up payments if you fall behind.

Smart Tips for Managing Quarterly Taxes

• Set aside 25–30% of your income each month.
• Use a separate savings account for taxes.
• Review your numbers quarterly to adjust if needed.
• Consider tax software or a CPA if your income varies widely.

FAQs About Self-Employed Taxes in Arizona

Do all self-employed workers in Arizona have to pay quarterly taxes?
Yes, if you expect to owe $1,000 or more in state tax.

What forms do I need for Arizona estimated tax?
Form 140ES-SBI for the state, Form 1040-ES for federal.

Are deadlines the same for state and federal?
Yes, both follow the April, June, September, and January schedule.

Can I adjust payments if income changes mid-year?
Yes, you can increase or decrease payments as needed.

How do I avoid penalties?
Pay 100% of last year’s liability or 90% of this year’s projected tax.