Freelancer Effective Tax Rate Calculator — 1099 Tax Estimator (2026)

Self-employment tax is often described as a flat 15.3%, and for most freelancers it effectively is. Above a certain income it is not, and the difference is large.

The 12.4% Social Security portion applies only up to the annual wage base — $184,500 in 2026. Beyond that, no more Social Security tax is due for the year.

The 2.9% Medicare portion has no ceiling at all, and above $200,000 for a single filer an Additional Medicare Tax of 0.9% applies on top.

So the marginal SE rate falls from 15.3% to 2.9% at the wage base, then rises slightly to 3.8%. On $400,000 of net profit, the correct calculation gives about $35,115 against $56,518 for the flat method — an overstatement of $21,403.

This matters for planning as well as accuracy. A freelancer approaching the wage base late in the year sees their marginal tax rate drop sharply, which is a genuine argument for accelerating income into the same tax year rather than deferring it.

The retirement one deserves emphasis because it is the largest lever most freelancers have. A solo 401(k) can shelter a substantial share of profit, reducing both income tax and — for the employer contribution — nothing of the SE tax, since SE tax is computed before retirement contributions. That asymmetry surprises people: retirement contributions cut your income tax but not your self-employment tax.

Half of SE tax —

automatic, and taken above the line whether or not you itemise. It is the employer half being treated as a business cost.

QBI (Section 199A) —

up to 20% of qualified business income, capped at 20% of taxable income before the deduction. Phases out for specified service businesses above an income threshold.

Home office —

either $5 per square foot up to 300 square feet, or the actual proportion of your housing costs. The space must be used regularly and exclusively for business — a laptop on the kitchen table does not qualify.

Health insurance —

fully deductible above the line if you are not eligible for a spouse's employer plan. One of the largest deductions available to a freelancer and frequently missed.

Retirement contributions —

a SEP-IRA takes up to 25% of net earnings; a solo 401(k) allows both employee and employer contributions and usually shelters more at moderate incomes.

Mileage —

the standard rate covers fuel, maintenance, insurance and depreciation. It requires a contemporaneous log — reconstructing one at tax time is exactly what an audit looks for.

The IRS expects tax to be paid as income is earned. Underpay and you owe a penalty, calculated as interest on the shortfall for each period it was outstanding.

Two safe harbours protect you regardless of what you eventually owe. Pay at least 90% of the current year's total tax, or 100% of last year's total tax — 110% if your prior-year adjusted gross income exceeded $150,000.

The prior-year safe harbour is the useful one for anyone whose income is volatile. If last year's tax was $17,800, paying $4,450 a quarter this year protects you from penalty even if you earn far more and end up owing much more. You still owe the balance at filing; you simply are not penalised.

For a freelancer whose income arrives unevenly, the annualised income instalment method allows payments matched to when income was actually earned, rather than four equal amounts. It requires more paperwork and it prevents the penalty that otherwise arises from a large fourth-quarter payment.

One practical trick: if you also have W-2 income, or a spouse does, increasing withholding covers the shortfall regardless of when in the year it happens. Withholding is treated as paid evenly across the year, which quarterly payments are not.

The working rule most freelancers arrive at is to set aside 25% to 30% of every payment received, in a separate account, and never treat it as available.

The exact figure comes out of this calculation — 17.8% federal on the worked example — plus state income tax where it applies, which ranges from nothing to over 13%. Thirty percent is a safe default for someone in a taxed state.

On entity choice: an LLC by itself changes nothing about tax. A single-member LLC is disregarded, and the income lands on Schedule C exactly as it would without one.

The S-corporation election is the change that matters. It lets you split income between a reasonable salary, which carries payroll tax, and distributions, which do not. Above roughly $60,000 to $80,000 of net profit the SE tax saving can exceed the cost of payroll processing and the additional return.

The cost side is real and often understated: payroll service, a separate business return, higher accounting fees, and the requirement that the salary be genuinely reasonable for the work. The IRS scrutinises artificially low salaries, and the penalty for getting it wrong is back payroll tax plus interest.

Below that threshold the S-corp usually costs more than it saves. It is a decision worth taking with an accountant once, rather than reading about repeatedly.