Understanding Tax Brackets and Effective Tax Rates for Small Business Owners (2025)

One of the most common misconceptions among small business owners is that their tax bracket IS their tax rate. It’s not. The 2025 federal brackets range from 10% to 37%, but your effective (average) tax rate is always lower than your marginal (top) bracket because income is taxed in layers: the first dollars are taxed at 10%, the next layer at 12%, and so on. A single filer with $100,000 in taxable income is in the “24% bracket” but pays an effective federal income tax rate of approximately 17%. On top of federal income tax, small business owners pay self-employment tax (15.3% on the first $176,100 of net earnings, 2.9% above that) and state income tax (0-13.3% depending on the state). The total combined rate for a typical small business owner earning $100,000 in net profit is approximately 25-33%, depending on filing status and state.

What’s the total tax rate for a small business owner?

What strategies can reduce self-employment tax?

The most common approach is electing S-Corp status, which lets you split business income between a reasonable salary (subject to payroll tax) and distributions (not subject to FICA). Maximizing legitimate business deductions reduces net profit and therefore the base for self-employment tax. Contributing to a SEP-IRA or solo 401(k) reduces income tax but does not reduce self-employment tax because the contribution is calculated after SE tax. Hiring your children under age 18 (for a sole proprietorship or spousal partnership) shifts income to them without triggering FICA on their wages. Forming a limited partnership where you are a limited partner can avoid SE tax on partnership income, but the IRS scrutinizes this closely for service businesses.

How is the self-employment tax calculated?

Self-employment tax is 15.3% on net self-employment income up to the Social Security wage base ($168,600 in 2024), then 2.9% on income above that threshold. Net self-employment income is calculated as 92.35% of your Schedule C net profit (the 7.65% reduction approximates the employer-half FICA deduction that W-2 workers receive). You deduct half of the self-employment tax on Schedule 1 of Form 1040, which reduces your AGI and income tax but does not reduce the SE tax itself. The additional Medicare tax of 0.9% applies to combined wages and self-employment income exceeding $200,000 ($250,000 married filing jointly). This makes the effective rate on high-income self-employment earnings 16.2%.

Related guides:

• Tax Brackets for Small Business Owners: Marginal vs. Effective Rate

How do you calculate the self-employment tax deduction?

The self-employment tax is 15.3% of net self-employment earnings (12.4% Social Security on income up to the wage base of $176,100 for 2025, plus 2.9% Medicare on all earnings). Before calculating the tax, you multiply net earnings by 92.35% (0.9235) to account for the fact that employees only pay tax on wages after the employer’s share is excluded. You deduct half of the self-employment tax as an above-the-line deduction on Form 1040, which reduces your AGI but not your self-employment income for SE tax calculation purposes. The additional 0.9% Medicare surtax applies to self-employment income exceeding $200,000 for single filers or $250,000 for joint filers, and this additional tax is not eligible for the 50% deduction.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.