One of the biggest surprises for newly self-employed people is discovering that taxes don't just happen once a year — they're due four times a year. Miss those quarterly payments, and you'll face underpayment penalties on top of your regular tax bill. Here's everything you need to know.

Why Quarterly Taxes Exist

The U.S. tax system operates on a pay-as-you-go basis. When you're an employee, your employer withholds taxes from every paycheck and sends them to the IRS on your behalf. When you're self-employed, there's no employer doing that — so you're responsible for making those payments yourself, four times a year.

The 2026 Quarterly Due Dates

• Q1 (January 1 – March 31): Due April 15, 2026
• Q2 (April 1 – May 31): Due June 16, 2026
• Q3 (June 1 – August 31): Due September 15, 2026
• Q4 (September 1 – December 31): Due January 15, 2027

How to Calculate What You Owe

There are two safe harbor methods that protect you from underpayment penalties:

• Pay 100% of last year's tax liability (110% if your AGI was over $150,000)
• Pay 90% of your current year's estimated tax liability

The simplest approach for most self-employed people: take your prior year's total tax bill, divide by four, and pay that amount each quarter. It's not perfect, but it keeps you penalty-free while you figure out your actual income for the year.

“The goal of quarterly estimated taxes isn't to pay exactly the right amount — it's to pay enough to avoid penalties while keeping your cash flow manageable.”

What Counts as Self-Employment Income

You need to make quarterly payments if you expect to owe at least $1,000 in federal taxes after withholding and credits. This applies to:

• Freelance and consulting income
• Business income from a sole proprietorship or single-member LLC
• Rental income (in some cases)
• Investment income if significant
• Side hustle income alongside a W-2 job