State estimated tax — 2026

Arizona Estimated Tax Payments 2026

Who has to make Arizona quarterly estimated payments, the 2026 due-date calendar, the safe-harbor rules that avoid an underpayment penalty, and how to pay through AZTaxes.gov.

Who must pay

Arizona’s rule is based on gross income, not a flat dollar amount of tax owed: you must make Form 140ES payments if your Arizona gross income exceeded $75,000 ($150,000 married filing jointly) for 2025 and you expect it to exceed that same threshold again for 2026. This is a separate test from the $1,000 prior-year-liability figure that governs whether a Form 221 penalty applies at all — don’t confuse the two.

2026 due-date calendar

Installment	% of annual estimate	Due date	Note
Q1	25%	April 15, 2026	—
Q2	25%	June 15, 2026	—
Q3	25%	September 15, 2026	—
Q4	25%	January 15, 2027	—

Arizona divides the required annual payment (the smaller of 90% of 2026 tax or 100% of 2025 tax) by four for equal 25% installments — the 100% prior-year option requires having filed an Arizona return for the prior year.

Safe harbor — avoiding the underpayment penalty

Arizona’s Form 221 penalty goes away if you pay whichever is smaller: 90% of what you actually end up owing for 2026, or 100% of your 2025 bill (that second path only works if you filed an Arizona return last year). There’s also an escape hatch that has nothing to do with percentages — a 2025 Arizona liability under $1,000, after withholding and credits, means no penalty applies at all.

How to calculate your payment

Estimate your annual Arizona tax, test it against the safe harbor above, then split the required annual payment across the installments in the calendar. The site's quarterly planner handles the math and the federal side together.

Open the quarterly estimated tax calculator → Check your underpayment penalty exposure →

How to pay

Pay online through AZTaxes.gov, or mail a check or money order with the Form 140ES voucher.

Penalty basics

Arizona’s underpayment penalty equals the interest that would accrue on the underpaid amount, capped at 10% of the underpayment. The Arizona Department of Revenue does not publish the numeric interest rate for the current period online — it sets the rate by statutory "rate period" and directs taxpayers to call ADOR (602-255-3381 in Phoenix, 800-352-4090 toll-free) for the figure in effect.

Arizona-specific notes

Arizona’s payment requirement is a GROSS INCOME test, not a tax-owed test: you’re on the hook if your Arizona gross income topped $75,000 single / $150,000 married filing jointly (also $75,000 for married filing separately and head of household) in the prior year and you expect to clear that bar again — even if your actual tax liability is modest at Arizona’s 2.5% flat rate.
The correct form is "Form 140ES" — not "AZ-140ES." The underpayment-penalty form is a separate document, Form 221.
A taxpayer whose 2025 Arizona tax liability (after withholding and credits) was under $1,000 owes no Form 221 penalty at all, independent of the gross-income filing requirement above.

See the Arizona 2026 tax brackets for current rates, or the Arizona state tax calculator to estimate your full-year liability.

Frequently asked questions

When are Arizona estimated tax payments due in 2026?

The four Arizona due dates for 2026 are April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Arizona divides the required annual payment (the smaller of 90% of 2026 tax or 100% of 2025 tax) by four for equal 25% installments — the 100% prior-year option requires having filed an Arizona return for the prior year.

Do I owe Arizona estimated tax based on how much I earn, or how much tax I owe?

How much you earn. Arizona’s requirement is triggered by gross income — $75,000 for single filers, $150,000 for married filing jointly — measured against both the prior year (2025) and your expectation for the current year (2026). That’s different from states like Colorado or New York, which key off the dollar amount of tax you expect to owe.

Is the Arizona estimated-tax form really called "AZ-140ES"?

No — the correct name is simply Form 140ES ("Individual Estimated Income Tax Payment"). The underpayment-penalty form, if you owe one, is the separate Form 221.

What interest rate does Arizona use for the underpayment penalty?

The Arizona Department of Revenue does not publish a numeric rate online — it changes by statutory rate period, and ADOR directs taxpayers to call its Phoenix (602-255-3381) or toll-free (800-352-4090) line for the current figure. What is published is the cap: the penalty can never exceed 10% of the underpaid amount, and taxpayers whose prior-year tax liability was under $1,000 owe no penalty regardless.

How do I pay Arizona estimated tax?

Pay online through AZTaxes.gov, or mail a check with the Form 140ES voucher.

Estimated tax in other states

Compare how Arizona stacks up against the other states with a Rising search trend for estimated-tax rules.