If you're self-employed or have significant income not subject to withholding, the IRS expects you to pay taxes quarterly — not just once a year in April. Missing these payments can result in underpayment penalties and a nasty surprise at filing time.
Who Must Pay Quarterly
You generally need to make estimated tax payments if you expect to owe $1,000 or more in federal tax after subtracting withholding and refundable credits. This applies to most self-employed individuals, business owners, landlords, and investors with significant capital gains.
The Four Deadlines
- Q1: April 15 (for income earned January through March)
- Q2: June 15 (April through May — yes, only two months)
- Q3: September 15 (June through August)
- Q4: January 15 of the following year (September through December)
Two Safe Harbor Methods
The IRS won't penalize you if you pay at least:
- 100% of last year's tax liability (110% if your AGI exceeds $150,000), divided into four equal payments, OR
- 90% of your current year's tax liability
How to Calculate Your Payments
The simplest approach: take last year's total tax liability from your return, divide by four, and pay that amount each quarter. If your income is growing significantly, work with your CPA to estimate current-year liability and adjust payments accordingly.
Don't Wait Until April
The biggest mistake we see is business owners who ignore estimated taxes all year and then scramble to find $30,000 or more in April. A simple quarterly payment plan eliminates the surprise and spreads the cash flow impact evenly throughout the year.