How to Calculate Estimated Taxes

Calculating estimated taxes follows a logical sequence. Whether you are a freelancer, contractor, or small business owner, this guide walks through each step so you understand exactly how quarterly payments are determined.

Step 1: Estimate Gross Income

Start with your total expected revenue from self-employment. Include all 1099 income, freelance payments, consulting fees, and business revenue. If you also have W-2 income, include that too, noting taxes are already withheld from W-2 wages.

Step 2: Subtract Business Expenses

Deduct ordinary and necessary business expenses: home office, equipment, software, travel, professional development, health insurance premiums, and other legitimate costs. This gives you net self-employment income.

Step 3: Calculate Self-Employment Tax

SE tax is 15.3% on 92.35% of net earnings. Social Security (12.4%) is capped at $176,100 for 2025. Medicare (2.9%) has no cap. Deduct half of SE tax from income to get your adjusted gross income.

Steps 4-7: Deductions and Tax Calculations

Apply your standard deduction ($15,000 Single, $30,000 MFJ for 2025) or itemized deductions. Calculate federal tax using bracket rates. Calculate state tax using your state rates. Add federal, state, and SE tax together for your total annual tax liability.

Steps 8-10: Calculate Quarterly Payment

Subtract any taxes already paid through withholding or prior estimated payments. Divide the remaining balance by the number of quarters left. Compare against safe harbor thresholds (90% of current year or 100%/110% of prior year) to ensure you avoid penalties. This entire process takes about 30 seconds with our calculator.