Self-Employment Tax Calculator

Why self-employment tax feels so much bigger

An employee pays 7.65% of wages toward Social Security and Medicare, and their employer quietly pays another 7.65% on their behalf. When you work for yourself you are both, so you pay the combined 15.3% — and you pay it on profit, not on salary, which means it is due whether or not you actually drew the money out of the business.

On the default figures here — $90,000 of net profit, single filer, standard deduction — that works out to $12,717 of self-employment tax before a dollar of income tax is calculated. Total federal tax comes to about $19,316, an effective rate of roughly 21.5%.

Two things soften it, and both are built into this calculator. First, SE tax applies to only 92.35% of your net profit, not all of it. Second, half of what you pay is deductible against your income tax. The combination is why the effective rate lands near 21% rather than the 30%-plus that a naive 15.3% plus your bracket would suggest.

The 92.35% rule and the deductible half

The government applies SE tax to 92.35% of net profit to mirror the fact that employees are not taxed on the employer half of FICA. On $90,000 of profit, the amount subject to SE tax is $83,115 — which is where the $12,717 comes from: 12.4% Social Security plus 2.9% Medicare.

Then half of that, $6,358, comes off your income before income tax is calculated. It is an above-the-line deduction, so you get it whether or not you itemize — you do not need to exceed the standard deduction to benefit.

Together these two provisions are worth several thousand dollars a year at this income level, and they are the reason a rough "15.3% of everything" mental estimate overstates the bill by a wide margin.

The strange shape of the effective rate

Run different profit levels through this and something counterintuitive appears. The effective tax rate rises with income up to a point, then falls:

• $30,000 profit — $5,181 total, about 17.3%.
• $50,000 profit — $9,732 total, about 19.5%.
• $90,000 profit — $19,316 total, about 21.5%.
• $120,000 profit — $28,462 total, about 23.7%.
• $200,000 profit — $53,431 total, about 26.7%.
• $300,000 profit — $76,695 total, about 25.6%.

The rate at $300,000 is lower than the rate at $200,000. The reason is that Social Security stops at an annual wage base — once your earnings pass that ceiling, the 12.4% Social Security component falls away and only Medicare continues. Income above the cap still faces the Additional Medicare Tax, but the combined rate drops.

Push further and the dip does not continue. The effective rate bottoms out near $280,000 at about 25.4%, then climbs again — 26.6% at $400,000 and 27.5% at $500,000 — because the progressive income tax eventually outweighs the benefit of the expiring Social Security component.

Income tax is progressive and keeps climbing, so total tax certainly keeps rising. It is the percentage that dips. The practical takeaway is that the self-employment penalty is proportionally heaviest in the middle ranges — roughly $80,000 to $200,000 — and lighter above the Social Security ceiling.

Where the Social Security cap actually bites

Two thresholds decide how much of the 15.3% you actually pay, and both move every year.

The Social Security wage base of $184,500 applies to the 92.35% figure, not to your profit — so the cap only starts to bind once net profit exceeds about $199,783. Below that, every dollar of profit carries the full 15.3%. Above it, the Social Security component stops growing and only Medicare continues.

The second threshold runs the other way. The Additional Medicare Tax of 0.9% kicks in once your combined earnings pass $200,000, which for a pure freelancer means profit of roughly $216,567. It is small next to the Social Security saving, so the net effect is still a falling rate — but it is why the dip is a dip rather than a collapse.

• Profit below about $199,783 — full 15.3% on the taxable 92.35%.
• Profit above that — 12.4% stops; only the 2.9% Medicare component grows.
• Profit above roughly $216,567 — the extra 0.9% Medicare surtax applies.

These are point-in-time values for the current tax year. The wage base in particular has risen substantially in recent years, which means the ceiling now sits higher above typical freelance income than it used to.

If you also have a W-2 job

This is a case that catches people out, and it works in your favour. Social Security is capped per person, not per job, and W-2 wages consume that cap first. Any cap your employer's wages use up is cap your self-employment income cannot reach — so your SE tax goes down.

Consider $90,000 of business profit alongside a day job. Your SE tax is calculated on $83,115 of profit, so the wages only start to help once they exceed $101,385 — the wage base of $184,500 minus that $83,115.

Below that point nothing changes: at $100,000 of wages, SE tax is still the full $12,717. Push past it and the effect appears quickly — $110,000 of wages brings SE tax to $11,648, $130,000 brings it to $9,286, and $150,000 brings it to $6,986.

Total tax still rises with the extra wages, of course. But the SE tax component specifically falls, and if you have both, entering the wages here is what makes the estimate accurate.

What the QBI deduction is worth

The qualified business income deduction allows many pass-through owners to deduct up to 20% of qualified business income. On these figures it comes to $13,508 and reduces the tax bill by about $2,972 — a meaningful amount that is easy to overlook when budgeting.

Real eligibility is more complicated than this tool models. The deduction is subject to income thresholds, and specified service businesses — commonly fields like law, medicine, consulting and financial services — face phase-outs above those thresholds. The calculation here also caps the deduction at 20% of net profit, which binds when taxable income before QBI is high relative to profit.

Treat the figure as an estimate of what the deduction would be worth if you qualify in full, and confirm the details for your situation before relying on it.

Paying it: quarterly estimated taxes

Nobody withholds SE tax for you, which means you have to send it in yourself. If you expect to owe $1,000 or more after any withholding and credits, you are generally required to make quarterly estimated payments — typically due mid-April, mid-June, mid-September and mid-January.

Underpaying carries a penalty even if you settle the balance by filing deadline, because the penalty is calculated on when the money should have been paid, not on whether you eventually paid it. This is the most common and most avoidable cost for new freelancers.

A workable approach for the first year is to set aside a fixed percentage of every payment received — the 21.5% effective rate here is a reasonable starting point at this income level, adjusted upward if you are in a state with income tax — and revisit it once you know your actual figures.

Business expenses change this more than anything

This calculator takes net profit, which is revenue minus deductible business expenses. Every legitimate deduction reduces both your income tax and your SE tax, because SE tax is levied on profit rather than revenue. A $5,000 expense at this income level cuts roughly $706 of SE tax alone — $5,000 × 92.35% × 15.3% — and about $1,516 off the total federal bill once the income tax effect is included.

That makes accurate expense tracking the highest-return activity available here — worth more per hour than almost anything else you can do about this tax.

Does an S-corporation help?

You will hear that an S-corp election reduces self-employment tax, and it can. The mechanism: an S-corp pays you a salary subject to payroll tax, while remaining profit flows through as distributions that are not subject to SE tax. Splitting income that way can cut the SE tax substantially at higher profit levels.

It is not free money. The salary must be reasonable for the work you do — the IRS tests this, and understating it invites reclassification. You take on payroll filings, quarterly returns and usually payroll service costs. At moderate profit levels the savings often do not exceed the added compliance burden.

It generally becomes worth modelling somewhere above the range where SE tax starts to hurt — often discussed once net profit is comfortably into six figures. Run your actual numbers and compare the full cost of administration before electing.

What this estimate does not include

This is a federal planning estimate. It is deliberately simplified, and several things it omits can be large.

• State and local income tax, which ranges from zero to well over 10% depending on where you live.
• Credits you may qualify for, and deductions beyond the standard one.
• Retirement contributions — a SEP-IRA or solo 401(k) can reduce taxable income substantially and is often the most powerful lever available.
• Self-employed health insurance premiums, which are generally deductible above the line.
• Local business taxes, gross receipts taxes or city-level filings.
• Prior-year items, carryforwards or amended returns.

Use it to size the set-aside and to compare scenarios — taking on more work, hiring, changing structure. Do not file from it. Confirm figures against current-year IRS guidance or a tax professional, particularly since the wage base, standard deduction and bracket thresholds in this tool are point-in-time values that change annually.