How Much Should You Reserve for Self-Employment Taxes?

Self-employment tax is based on your net business profit, not your gross revenue, and the calculation applies a 92.35% factor before the Social Security and Medicare taxes are calculated.

Start with net profit

For example, if a business generates $120,000 in revenue and has $20,000 in business expenses, the starting point for the self-employment tax calculation is $100,000 of net profit, not $120,000 of revenue. This amount, referred to as Schedule C profit, is then multiplied by 92.35% to determine net earnings subject to self-employment tax.

The resulting figure is then subject to a 12.4% Social Security tax and a 2.9% Medicare tax, for a combined rate of 15.3%.

The calculation can be summarized as:

Net Schedule C profit × 92.35% = net earnings subject to self-employment tax → Social Security + Medicare = total self-employment tax

Using $100,000 of net profit:

$100,000 × 92.35% = $92,350

That $92,350 becomes the earnings base used for the Social Security and Medicare portions of the calculation. Now we can arrive at the estimated self-employment tax amount.

For the $100,000 example:

• Net Schedule C profit: $100,000
• Net earnings subject to self-employment tax: $92,350
• Social Security tax at 12.4%: $11,451.40
• Medicare tax at 2.9%: $2,678.15
• Total self-employment tax: $14,129.55

The Social Security and Medicare portions also have different rules, which become more relevant at higher income levels. The Social Security portion is subject to an annual wage base, meaning earnings above that threshold are not subject to the regular 12.4% Social Security tax. The regular Medicare portion has no wage-base limit, and an additional 0.9% Medicare tax may apply at higher income levels.

Net profit is the main variable

Because net Schedule C profit is the starting point, changes in business revenue or expenses can change the self-employment tax calculation.

For example, increasing deductible business expenses can reduce net profit. That lower profit then produces a lower net earnings base after the 92.35% adjustment, which in turn changes the Social Security and Medicare amounts.

This is why self-employment tax should not be thought of as a fixed percentage of gross revenue. The relationship begins with net business profit.

Try it yourself

Change only the Net Schedule C Profit input and compare the results.

Watch three numbers:

• Net earnings subject to self-employment tax
• Social Security tax
• Medicare tax

The purpose is to see how a change in business profit flows through the calculation rather than treating the 15.3% rate as a standalone percentage.

The deductible portion has a different purpose

The calculator also shows a deductible portion of the self-employment tax. In the $100,000 example, half of the $14,129.55 self-employment tax is $7,064.78.

This is not an additional amount to reserve for self-employment tax. It is a deduction that affects the separate federal income tax calculation.

That distinction matters because $14,129.55 and $7,064.78 represent different things. The first is the self-employment tax calculated from the business income. The second is the deductible portion used when determining income for federal income tax purposes. The deduction is not itself a $7,064.78 tax savings.

The same self-employment tax calculation can also matter when considering other calculations for self-employed income. For example, the Self-Employed Health Insurance Deduction calculator uses related self-employment income information and can incorporate the deductible portion of self-employment tax as part of that calculation.

What the self-employment tax amount means

The self-employment tax amount represents the Social Security and Medicare taxes calculated from your net business profit after the 92.35% adjustment.

It does not represent your entire federal tax obligation. Federal income tax is a separate calculation, and the deductible portion of self-employment tax affects that calculation. State and local taxes may also be separate considerations.

The key numbers therefore have different purposes. Net business profit is the starting point, the 92.35% figure determines the net earnings base, and the resulting Social Security and Medicare amounts produce the self-employment tax. The deductible portion affects the separate federal income tax calculation rather than increasing or decreasing the amount of self-employment tax itself.

If the next question is whether a particular 1099 arrangement makes financial sense after considering taxes and business expenses, the 1099 Tax & Contract Evaluator addresses that broader decision.