Quarterly estimates, explained

Employees pay tax all year through withholding. Self-employed people are expected to do the same thing themselves, four times a year. Miss it and the IRS charges a penalty — even if you pay every dollar you owe in April.

Who has to pay

You, if you expect to owe $1,000 or more in federal tax after subtracting any withholding and credits. That covers almost every full-time gig driver or contractor, and many people with a side business alongside a W-2 job.

When they're due

Income earned	Payment due
January 1 – March 31	April 15
April 1 – May 31	June 15
June 1 – August 31	September 15
September 1 – December 31	January 15 (following year)

If a date falls on a weekend or holiday, it moves to the next business day. Most states with an income tax use the same schedule.

How much

There are two ways to be safe from the penalty:

1. Pay 90% of what you'll actually owe this year, in four roughly equal payments. Accurate but requires forecasting.
2. Pay 100% of last year's total tax (110% if your income was over $150,000), in four equal payments. Simple and penalty-proof, even if you earn far more this year — you'd just owe the difference in April, with no penalty.

Most people with steady income use option 2. People whose income jumped or dropped use option 1. We calculate both and put the numbers on your vouchers when we prepare your return.

How to pay

Federal: IRS Direct Pay (irs.gov/payments) from a bank account, free, takes two minutes; select "Estimated tax" and the tax year. Or mail Form 1040-ES with a check. State: your state's revenue department website (Arizona uses AZTaxes.gov and Form 140ES).

A shortcut if you also have a W-2 job

You can skip estimates entirely by having your employer withhold more — file a new W-4 and add an extra flat amount per paycheck. Withholding counts as paid evenly through the year no matter when it happens, which makes it even more forgiving than estimates.

Keep the record

Save the confirmation for every payment. When you file, the return has to show the exact dates and amounts, and the IRS's own records aren't always right.

This is general information, not advice for your specific return. Thresholds and dates change; confirm current ones before relying on them.