Quarterly Estimated Taxes: The System That Keeps You Out of Trouble

How to calculate what you owe, when to pay it, and how to stop dreading April

Here is something that surprises a lot of new self-employed business owners: the IRS does not want to wait until April 15th to collect your taxes. The U.S. tax system is a pay-as-you-go system — meaning the government expects taxes to be paid throughout the year, as you earn the income. When you were an employee, your employer handled this automatically through payroll withholding. When you are self-employed, that job falls on you. Enter: quarterly estimated taxes.

What Are Quarterly Estimated Taxes?

Estimated taxes are prepayments of your expected tax liability for the year — both income tax and self-employment tax. They are paid four times a year, on a schedule set by the IRS.

The four deadlines are: April 15 (for income earned January through March), June 16 (for income earned April through May), September 15 (for income earned June through August), and January 15 of the following year (for income earned September through December).

Note that the periods are not equal quarters — the second period is only two months. This trips people up.

Who Needs to Pay Them?

You generally need to make estimated tax payments if you expect to owe at least $1,000 in federal taxes for the year after subtracting withholding and credits, and your withholding and credits will cover less than 90% of your current year tax liability OR less than 100% of your prior year tax liability (110% if your prior year AGI was over $150,000).

For most self-employed individuals and small business owners, this means quarterly payments are required. The question is not whether to pay — it is how much.

How to Calculate What You Owe

There are two main methods:

The Prior Year Safe Harbor Method: Pay at least 100% of your prior year tax liability (or 110% if your income was over $150,000 in the prior year), divided across the four payment periods. This method protects you from underpayment penalties even if your current year income is higher than expected.

The Current Year Estimation Method: Estimate your current year income and expenses, calculate your projected tax liability, and pay 90% of that across the four periods. This is more precise but requires more work and carries more risk if your estimates are off.

For most business owners, the prior year safe harbor method is simpler and safer as a baseline. You can adjust throughout the year if your income changes significantly.

The Simple Rule That Works

For every dollar of business income you receive, set aside 25 to 30% in a dedicated savings account. Call it your tax account. Do not touch it for anything else. When quarterly payment deadlines arrive, make your payment from that account.

This approach will not be perfectly precise — but it keeps you from spending tax money that is not yours, and it prevents the painful scramble of coming up with a large lump sum in April.

Payments can be made online through IRS Direct Pay or the Electronic Federal Tax Payment System (EFTPS). Both are free and take minutes.

What Happens If You Miss a Payment?

Missing or underpaying a quarterly estimate does not trigger an audit — but it does trigger an underpayment penalty. The IRS calculates this as interest on the amount you should have paid, for the period it was unpaid. It is not catastrophic, but it adds up — and it is entirely avoidable.

The time to get this system in place is before your income grows to a level where the penalties become meaningful. Build the habit early.