Do I Have to Pay Both Income Tax and Self-Employment Tax on Side Money?
The first year of freelance or side-gig income often comes with a surprising realization: the tax bill isn’t just income tax, there’s a second tax layered on top. It can feel like being taxed twice for the same dollar, but the two taxes are doing different jobs.
The short answer
Yes, self-employment income is generally subject to both regular income tax and a separate self-employment tax. The self-employment tax covers Social Security and Medicare contributions that an employer would normally split with an employee through payroll withholding. Because side income usually has no employer handling that half, the person earning it is generally responsible for covering both portions themselves, in addition to whatever income tax applies to their overall earnings.
Why there are two separate taxes
Income tax is based on total earnings from all sources and funds general government spending, while the self-employment tax specifically funds Social Security and Medicare, the same programs a paycheck’s payroll withholding funds for a traditional employee. When someone works a regular job, the employer pays half of those payroll contributions automatically. Self-employment tax exists so that people earning money outside of traditional employment still contribute to those same programs, just structured differently since there’s no employer to split it with.
How the two taxes interact
- They’re calculated on different bases. Self-employment tax applies to net self-employment earnings after business expenses are subtracted, while income tax applies to total taxable income from every source, including a regular job’s wages if there is one.
- A deduction helps offset the overlap. A portion of the self-employment tax paid is generally deductible when calculating income tax, which softens the effect of the two taxes stacking on the same earnings.
- Both need to be accounted for when estimating what’s owed. Someone with steady side income may need to think about setting up a payment plan for taxes owed if the combined total catches them off guard at filing time.
What counts as self-employment income
Money earned from freelance work, gig platforms, selling goods or services independently, or running a small side business generally counts, regardless of whether it’s paid through a payment app, cash, or check. This is different from a regular paycheck, where taxes are already withheld throughout the year. Because of that, it’s common for a payment app to issue its own tax form reflecting side income that wouldn’t otherwise show up automatically, which is part of why tracking this income separately from a main job’s wages matters.
Planning ahead for the combined bill
Because neither tax is withheld automatically from side income the way it is from a paycheck, some people set aside a portion of each payment as it comes in, treating it similarly to how an emergency fund gets built through steady, smaller contributions rather than one lump sum. Others make estimated payments throughout the year to avoid a large bill, and potentially a penalty, at filing time. How much to set aside depends on total income for the year, deductible business expenses, and other factors, so checking current guidance or working with a tax professional helps avoid guessing.
Where this leaves you
Side income being subject to both income tax and self-employment tax isn’t a special penalty for freelancing — it reflects that no employer is splitting Social Security and Medicare contributions on that money. Understanding that the two taxes are calculated differently, and planning to set money aside throughout the year rather than at filing time, tends to make the total less of a surprise.