How Self-Employment Tax Works — And Why Your Deductions Are Worth More Than You Think

What Is Self-Employment Tax?

When you work as a traditional employee, your employer pays half of your Social Security and Medicare taxes (called FICA taxes) and you pay the other half through payroll withholding. As a self-employed gig worker, you are both the employer and the employee — which means you pay both halves yourself.

That combined rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare. It applies to your net self-employment income — your gig earnings after deducting business expenses.

There is one small break: the IRS does not apply SE tax to 100% of your net income. It applies to 92.35% of it (that is, 100% minus the 7.65% employer share). This is a longstanding quirk of the tax code that slightly reduces your SE tax burden.

The Deductible Half — A Hidden Benefit

Here is where gig workers get a break that is easy to miss: you can deduct half of your self-employment tax from your gross income when calculating your federal income tax. This mirrors what regular employers do — they deduct their half of FICA as a business expense.

Concretely: if you owe $3,000 in SE tax for the year, you can deduct $1,500 from your gross income on your Form 1040. This deduction reduces your federal (and in some states, state) taxable income — on top of any Schedule C deductions you already claimed.

This is an above-the-line deduction, meaning you get it whether you itemize or take the standard deduction.

Why Gig Worker Deductions Save More Than You Expect

When you deduct a business expense on Schedule C, you reduce your net self-employment income. That reduced income flows through your return in three distinct ways, each generating tax savings:

1. SE tax savings: Lower net income means lower self-employment tax. For every $100 you deduct, you save approximately $14.13 in SE tax (that is, $100 × 92.35% × 15.3%).
2. Federal income tax savings: That same $100 deduction reduces your federal taxable income. At the 22% bracket, that is another $22 in savings. At the 12% bracket, $12.
3. State income tax savings: In California, for example, that $100 deduction reduces state taxable income as well, saving an additional $4–$13 depending on your state bracket.

Add those three layers together and a gig worker in the 22% federal bracket in California saves approximately 38–40 cents for every $1 of deductible business expense. A worker in the 12% bracket saves approximately 26–28 cents per dollar. These are numbers that W-2 employees do not have access to — only self-employed workers with Schedule C deductions get the SE tax savings layer.

The Qualified Business Income (QBI) Deduction

If your net self-employment income is below approximately $75,000 (single) or $150,000 (married filing jointly), you may also qualify for the Qualified Business Income (QBI) deduction — a 20% deduction off your net business income that further reduces your federal taxable income. This deduction was made permanent under recent tax legislation.

Note that California does not recognize the QBI deduction at the state level. It is a federal-only benefit. If you are filing in California, your state tax calculation excludes QBI — which is one reason federal and state savings rates differ for the same purchase.

Quarterly Estimated Taxes — What Gig Workers Owe and When

Unlike W-2 employees, no taxes are withheld from your gig income. The IRS requires self-employed workers to pay taxes four times per year through estimated payments. The 2026 due dates are:

• April 15 (for income earned January 1 – March 31)
• June 16 (for income earned April 1 – May 31)
• September 15 (for income earned June 1 – August 31)
• January 15, 2027 (for income earned September 1 – December 31)

If you skip or underpay quarterly taxes and owe more than $1,000 at filing, the IRS charges an underpayment penalty — even if you pay everything by April 15. The safe harbor rule: if you pay at least 100% of what you owed in the prior year (or 90% of what you owe in the current year), no penalty applies.

A simple approach: set aside 25–30% of every gig payment you receivein a separate savings account and pay quarterly. Your deductions reduce what you owe, so tracking business expenses throughout the year also reduces your quarterly payment obligation.

What This Means for Buying Work Equipment

Every legitimate business purchase — a phone mount, a dash cam, an insulated delivery bag, cleaning supplies — reduces your net SE income, which reduces your SE tax, your federal income tax, and your state income tax simultaneously. The sticker price on Amazon is not what the item costs you. The real cost is the sticker price minus all three layers of tax savings.

For a delivery driver in California earning $42,000 per year, a $100 work supply on Amazon effectively costs closer to $70–75 once all three savings layers are factored in. For a driver in a higher bracket, it may cost as little as $60.