What it means
Self-employment tax exists because social insurance systems are normally funded by two matching payments: one deducted from the worker's pay and one paid by the employer on top. A sole trader, freelancer or partner in a partnership is both parties at once, so they carry both halves of the bill themselves.
In the United States this tax is made up of Social Security at 12.4% and Medicare at 2.9%, giving a combined rate of 15.3%. The Social Security portion only applies up to an annual earnings ceiling that is adjusted each year, while the Medicare portion applies to every dollar of net earnings with no upper limit.
The base for the calculation is not your revenue and not your take-home drawings. It is your net profit, meaning sales minus allowable business costs, and only 92.35% of that profit is actually charged.
That 92.35% adjustment exists to mirror the fact that an employer's own share of payroll tax is a deductible business cost. This matters commercially because it changes what a day of freelance work is really worth.
Someone quoting $600 a day needs to remember that income tax and roughly 15% self-employment tax both come out of the margin, which is why experienced contractors price well above the salaried equivalent of the same role. There is partial relief built into the system: half of the self-employment tax you pay is deductible when working out your income tax, which softens the effective cost.
Owners of limited companies often face a different picture again, because salary and dividends or distributions are taxed under separate rules, and that difference is one of the main reasons small businesses consider changing their legal structure.
In practice
Real-world examples.
Example
A freelance copywriter bills $95,000 in her first full year and spends $15,000 on equipment, an accountant and a co-working desk. Her net profit is $80,000, so she budgets a little over $11,300 for self-employment tax on top of income tax. She moves 30% of every client payment into a separate savings account so the bill never surprises her.
Example
A two-partner landscaping partnership splits a $180,000 net profit evenly. Each partner is individually liable for self-employment tax on their own $90,000 share, so neither can point to the business as the payer. The partnership agreement is rewritten to require quarterly distributions large enough to cover each partner's estimated tax.
Example
A software engineer leaves a salaried role paying $140,000 for a contract paying $160,000. Once he adds self-employment tax, lost employer pension contributions and his own health cover, he calculates that the contract is worth slightly less in net terms. He renegotiates the day rate before signing.
Think of it
“Self-employment tax is FICA for freelancers-you pay both shares.
Formula
Calculation
Self-Employment Tax = Net Business Profit x 92.35% x 15.3%
Take a freelance product designer with net business profit of $80,000 for the year, after deducting software subscriptions, insurance and travel costs.
Step 1, find the taxable base: $80,000 x 0.9235 = $73,880.
Step 2, apply the two components. Social Security: $73,880 x 12.4% = $9,161.12. Medicare: $73,880 x 2.9% = $2,142.52.
Step 3, add them together: $9,161.12 + $2,142.52 = $11,303.64. That is the same as applying the combined 15.3% rate directly: $73,880 x 0.153 = $11,303.64.
Half of that figure, $5,651.82, is deductible against income tax, so the designer should set aside the full $11,303.64 in cash but should expect part of it back through a lower income tax bill.Case study
Seen in the real world.
The following is an illustrative, fictional example. Bramble Lane Bakes was a one-person artisan bakery that spent its first year selling at weekend markets. The owner tracked revenue closely, saw $110,000 of sales, and assumed that the $28,000 she had set aside would comfortably cover her tax bill.
Her accountant showed her that after $34,000 of ingredient, stall and van costs, her net profit was $76,000, and that self-employment tax alone would come to roughly $10,700 before any income tax was calculated. The shortfall was manageable but uncomfortable, and it forced her to delay buying a second oven by six months.
For the following year she changed two things. She raised prices by 8% on her slowest-margin lines, and she set a standing instruction to move 32% of every market day's takings into a tax account. By the time the next return was due, the money was already sitting there and the oven purchase went ahead on schedule.
Watch out
Common mistakes.
- Calculating self-employment tax on total revenue rather than on net profit after allowable business expenses, which badly overstates the bill and discourages people from trading.
- Forgetting that self-employment tax sits on top of income tax, so a freelancer who saves only for income tax ends up short every single year.
- Ignoring the deduction for half of the tax paid, which means the effective cost is lower than the headline 15.3% suggests once income tax is recalculated.
Questions
People also ask.
Do I owe self-employment tax if my business made a loss?
No, the tax applies to net earnings, so a genuine trading loss for the year means no self-employment tax for that year.
Does incorporating remove self-employment tax?
Not automatically, because salary paid by a company carries its own payroll taxes, but the split between salary and distributions can change the total, which is worth modelling with an accountant.
Should I pay it once a year or in instalments?
Most self-employed people are expected to pay estimated amounts during the year rather than in one lump sum, and paying quarterly also makes cash flow far easier to manage.
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