Arizona Quarterly Tax Calculator
Calculate your estimated quarterly tax payments for federal and Arizona state taxes. Designed for self-employed individuals, freelancers, and independent contractors.
AZ State Tax: Flat 2.5%
Quarterly Payment Amount
$6,058
Per quarter (4 remaining)
Annual Tax Breakdown
2026 Payment Schedule
Jan 1 - Mar 31
Due: April 15, 2026
$6,058
Apr 1 - May 31
Due: June 15, 2026
$6,058
Jun 1 - Aug 31
Due: September 15, 2026
$6,058
Sep 1 - Dec 31
Due: January 15, 2027
$6,058
Don't miss your quarterly payments!
The IRS may charge penalties and interest if you underpay or pay late. Consider setting up automatic payments or calendar reminders.
Arizona Quarterly Tax Highlights
Arizona has a flat 2.5% income tax rate
One of the lowest flat tax rates in the country
Use Form 140ES for quarterly estimated payments
Simple tax calculation with single flat rate
Arizona Quarterly Tax FAQ
What is Arizona's income tax rate for self-employed?
Arizona has a flat 2.5% income tax rate for all income levels. This applies to self-employed individuals as well. Combined with federal taxes and self-employment tax, self-employed Arizonans have a relatively low state tax burden.
When are Arizona quarterly taxes due?
Arizona quarterly estimated tax payments are due April 15, June 15, September 15, and January 15. Use Arizona Form 140ES to make your estimated tax payments.
Arizona Estimated Quarterly Tax Payments for Self-Employed Workers in 2026
Self-employed workers in Arizona face two tax obligations: federal estimated taxes filed with the IRS and state estimated taxes filed with the Arizona Department of Revenue. Arizona imposes a flat 2.5% income tax rate on all taxable income. If you expect to owe $1,000 or more in Arizona state income tax after withholding and credits, you must make quarterly estimated payments using Form 140ES.
Arizona's flat 2.5% rate, effective since 2023, is one of the lowest state income tax rates in the country. The state previously had a progressive system with rates up to 4.5%.
| Tax Layer | Rate / Range | Filed With | Form |
|---|---|---|---|
| Federal income tax | 10% – 37% | IRS | 1040-ES |
| Self-employment tax | 15.3% | IRS | 1040-ES / SE |
| Arizona state income tax | 2.5% | Arizona Department of Revenue | Form 140ES |
How Arizona's Flat 2.5% Income Tax Affects Your Quarterly Payments
Arizona uses a flat tax rate of 2.5%, which simplifies quarterly tax calculations. Regardless of income level, every dollar of taxable income is taxed at the same rate. This makes it straightforward to estimate your state quarterly payments — simply multiply your projected net self-employment income by 2.5% and divide by four.
For a single self-employed worker in Arizona earning $100,000 in net self-employment income, the estimated annual tax breakdown is:
| Tax Component | Estimated Amount | Calculation Basis |
|---|---|---|
| Federal income tax | ~$11,600 | After $15,700 standard deduction, 2026 brackets |
| Self-employment tax | ~$14,130 | 15.3% on 92.35% of net earnings |
| Arizona state income tax | ~$2,500 | 2.5% flat rate |
| Total annual tax | ~$28,230 | |
| Quarterly payment | ~$7,058 | Total / 4 quarters |
State payments can be made online through the Arizona Department of Revenue portal at azdor.gov, by mail with a Form 140ES voucher, or via electronic funds transfer where available.
Federal Self-Employment Tax and Quarterly Due Dates
All self-employed workers must pay federal self-employment (SE) tax of 15.3% on 92.35% of net earnings. This consists of 12.4% for Social Security (on earnings up to $184,500 in 2026) and 2.9% for Medicare (no cap). An additional 0.9% Medicare surtax applies to earnings above $200,000 (single filers).
Both Arizona and federal estimated tax payments follow the same quarterly schedule:
| Quarter | Income Period | Due Date |
|---|---|---|
| Q1 | January 1 – March 31 | April 15, 2026 |
| Q2 | April 1 – May 31 | June 15, 2026 |
| Q3 | June 1 – August 31 | September 15, 2026 |
| Q4 | September 1 – December 31 | January 15, 2027 |
To avoid underpayment penalties, pay at least 100% of your prior-year tax liability (or 110% if your AGI exceeds $150,000) spread across four equal payments, or at least 90% of your current-year tax. You can deduct 50% of your self-employment tax from your adjusted gross income, reducing both your federal and Arizona taxable income.
Related Calculators
Official References
This calculator uses current federal and Arizona tax rates and schedules:
- IRS Estimated Tax Guidelines
Federal quarterly tax requirements and Form 1040-ES
- Arizona Department of Revenue
Official Arizona tax authority
- Arizona Form 140ES
Arizona estimated tax payment form
- IRS Self-Employment Tax
Social Security and Medicare tax information
This calculator provides estimates based on 2026 tax rates. Your actual tax liability may vary based on deductions, credits, and other factors. Consult a tax professional for personalized advice.