Illinois Self-Employment Tax Calculator
Work out what a 1099 contractor, freelancer or sole proprietor really owes in Illinois: federal self-employment tax, federal income tax, the 4.95% state tax, and the quarterly estimated payment those add up to.
Illinois Self-Employment Tax Calculator
- Net earnings from self-employment 92.35% of profit$0.00
- Social Security portion 12.4%$0.00
- Medicare portion 2.9%$0.00
- Additional Medicare 0.9%$0.00
- Self-employment tax$0.00
- Deductible half of SE tax$0.00
- QBI deduction$0.00
- Federal income tax$0.00
- Illinois income tax 4.95%$0.00
- Total tax for the year$0.00
- Profit after tax$0.00
The three taxes a self-employed Illinoisan pays
Working for yourself does not create a new category of tax so much as it moves an existing one onto your side of the ledger. An employee and a freelancer earning the same amount pay similar totals — the freelancer just pays both halves of FICA and writes the paychecks themselves.
- Self-employment tax, 15.3%. This is Social Security at 12.4% and Medicare at 2.9%, applied to 92.35% of net profit. The Social Security portion stops at the $184,500 wage base for 2026; the Medicare portion never stops, and adds 0.9% above $200,000 for a single filer.
- Federal income tax. Ordinary graduated rates on business profit after the deductible half of SE tax, the QBI deduction and your standard or itemized deduction.
- Illinois income tax, 4.95%. Flat, and on profit rather than on a separate base. Illinois has no self-employment deduction of its own, but because its base income starts from federal adjusted gross income, the deductible half of the federal SE tax carries through to the state return.
A worked example: $80,000 of net profit
| Step | Amount |
|---|---|
| Net profit from Schedule C | $80,000.00 |
| Net earnings from self-employment (× 92.35%) | $73,880.00 |
| Social Security portion (12.4%) | $9,161.12 |
| Medicare portion (2.9%) | $2,142.52 |
| Self-employment tax | $11,303.64 |
| Deductible half of SE tax | −$5,651.82 |
| QBI deduction (20%) | −$16,000.00 |
| Standard deduction, single | −$16,100.00 |
| Federal taxable income | $42,248.18 |
| Federal income tax | $4,821.78 |
| Illinois base income ($80,000 less the deductible half of SE tax) | $74,348.18 |
| Illinois income tax (4.95%) | $3,680.23 |
| Total tax for the year | $19,805.66 |
| Each quarterly payment | $4,951.41 |
That is an effective rate of about 24.8% on the profit — which is why "set aside a quarter of everything" is a reasonable starting point for a freelancer at this income level, and why it is not enough at higher ones.
Quarterly estimated payments
The United States runs a pay-as-you-go tax system. An employee satisfies that through withholding; a self-employed person satisfies it through four estimated payments a year.
| Payment | Income period | Due date |
|---|---|---|
| Q1 | January 1 – March 31 | April 15 |
| Q2 | April 1 – May 31 | June 15 |
| Q3 | June 1 – August 31 | September 15 |
| Q4 | September 1 – December 31 | January 15 of the next year |
Federal payments use Form 1040-ES or the IRS Direct Pay service. Illinois payments use Form IL-1040-ES or MyTax Illinois. Illinois requires estimated payments if you expect to owe more than $1,000; the federal threshold is the same.
You avoid an underpayment penalty if your payments cover at least 90% of this year's tax or 100% of last year's total tax — 110% if your prior-year adjusted gross income exceeded $150,000. Paying last year's figure in four equal installments is the simplest way to stay protected while your income is growing.
Deductions that reduce both taxes
A business expense is unusually valuable to a self-employed person because it reduces net profit, which reduces income tax and self-employment tax. For someone in the 22% federal bracket in Illinois, a legitimate $1,000 expense saves roughly $370 — 22% federal, 4.95% Illinois and 14.13% effective SE tax.
- Home office — either the simplified $5 per square foot up to 300 square feet, or the actual-expense method apportioned by floor area. The space must be used regularly and exclusively for the business.
- Vehicle mileage — the standard rate covers fuel, insurance, maintenance and depreciation. Keep a contemporaneous log; reconstructing one later is the most common audit failure.
- Self-employed health insurance — premiums for you, your spouse and dependents, deductible above the line, though not against self-employment tax.
- Retirement contributions — a SEP-IRA allows up to 25% of net self-employment earnings; a solo 401(k) allows an employee deferral plus an employer contribution and usually shelters more at moderate incomes.
- Equipment, software and subscriptions — Section 179 or bonus depreciation can accelerate the deduction for larger purchases.
- Professional services — accountancy, legal fees, business insurance and license renewals.
1099 contractor versus W-2 employee in Illinois
| W-2 employee | 1099 contractor | |
|---|---|---|
| Social Security & Medicare | 7.65% — employer pays the other half | 15.3% — you pay both halves |
| Income tax | Withheld each payday | Four estimated payments a year |
| Illinois income tax | 4.95%, withheld | 4.95%, paid with estimates |
| Business expenses | Not deductible | Fully deductible against profit |
| Retirement limit | 401(k) elective deferral | SEP-IRA or solo 401(k), usually higher |
| Unemployment insurance | Covered | Not covered |
| Illinois workers' compensation | Covered by the employer | Your own responsibility |
The rule of thumb is that a contract rate needs to be roughly 25–30% above the equivalent salary to leave you in the same position, once the employer's FICA share, unpaid time off and self-funded benefits are accounted for. If you also hold a W-2 job, enter those wages in the calculator — they use up part of the Social Security wage base before your self-employment income touches it. Employees can compare the other side using the Illinois salary calculator.
Illinois applies a strict test — particularly in construction, under the Employee Classification Act — and a worker who behaves like an employee is one regardless of what the contract says. Misclassification exposes the hiring business to back taxes, penalties and unpaid overtime claims.
Related Illinois calculators
Hourly paycheck calculator
Regular hours, overtime at time and a half, double time and a second pay rate — all in one paycheck.
Salary & take-home calculator
Turn an annual salary into weekly, bi-weekly, semi-monthly and monthly net pay.
Bonus tax calculator
See what a bonus is worth after the flat 22% federal supplemental rate and Illinois withholding.
Self-employment tax calculator
1099 and Schedule C income: SE tax, federal tax, Illinois tax and your quarterly estimated payment.
Unemployment benefits calculator
Estimate your IDES weekly benefit amount from your base-period wages and dependent status.
Wage garnishment calculator
Work out the most a judgment creditor can take under the Illinois 15% and 45× minimum wage tests.
People also ask about self-employment tax in Illinois
Not a separate one, no. "Self-employment tax" is a federal tax of 15.3% that covers the Social Security and Medicare contributions an employer would otherwise split with you. Illinois adds only its ordinary flat income tax of 4.95% on the profit — there is no state-level SE tax and no separate rate for freelancers. Because Illinois base income starts from federal adjusted gross income, the deductible half of your SE tax reduces the Illinois figure too; the QBI deduction, which is claimed after AGI, does not.
A practical rule is 25% to 32% of net profit for most Illinois freelancers with no other income. On $80,000 of profit that works out to roughly $19,800 across self-employment tax, federal income tax and Illinois income tax — just under 25%. Set aside less than 25% and you will almost certainly come up short; the safest approach is to move a fixed percentage of every payment into a separate account the day it arrives. The calculator above gives you the exact percentage for your own numbers.
Federal and Illinois estimated payments share the same four dates: April 15, June 15, September 15 and January 15 of the following year. Federal payments go on Form 1040-ES; Illinois payments go on Form IL-1040-ES or through MyTax Illinois. You must make Illinois estimated payments if you expect to owe more than $1,000 after withholding and credits. Missing a due date triggers an underpayment penalty even if the year-end return shows a refund.
It is the adjustment that puts you on the same footing as an employee. An employer's share of FICA is a deductible business expense, so the tax code lets the self-employed reduce net profit by 7.65% — which is what multiplying by 0.9235 does — before applying the 15.3% rate. On $80,000 of profit, net earnings from self-employment are $73,880, and 15.3% of that is $11,303.64 rather than $12,240.
On your federal return, yes — the employer-equivalent half of the Social Security and Medicare portions is an above-the-line deduction that reduces adjusted gross income. It does not reduce the self-employment tax itself, only the income tax on top. The Additional Medicare Tax of 0.9% is not deductible. Illinois starts from federal AGI, so the deduction flows through to your Illinois return automatically.
The qualified business income deduction lets most sole proprietors, partners and S-corporation shareholders deduct up to 20% of qualified business income on the federal return. It is a deduction against taxable income rather than a business expense, so it does not reduce self-employment tax. Above the income thresholds the rules tighten — specified service businesses such as law, accounting, consulting and health face a phase-out, and wage and property limits apply. Illinois does not follow the QBI deduction, because it begins from federal AGI and QBI is claimed after AGI.
Anything ordinary and necessary for the business: home office space used regularly and exclusively for work, mileage at the standard rate, health insurance premiums, professional software and subscriptions, business insurance, continuing education, a portion of your phone and internet, professional fees, and retirement contributions to a SEP-IRA or solo 401(k). Every dollar of legitimate expense reduces both your income tax and your self-employment tax, which makes deductions worth roughly 30–40 cents on the dollar for a typical Illinois freelancer — a far better return than the income-tax saving alone suggests.
A sole proprietor working under their own legal name generally does not need to register with the state, though you may need a local business license depending on your municipality. If you trade under a different name you file an assumed name registration with your county clerk. You must register with the Illinois Department of Revenue through MyTax Illinois if you sell taxable goods and need to collect sales tax, or if you hire employees and need a withholding account.
Sources
- IRS — Self-employment tax
- IRS — Estimated taxes
- Illinois Department of Revenue — Estimated payments
- IRS — Qualified business income deduction
Estimates only. Self-employment tax outcomes depend on business structure, deductions, credits and other household income. Speak to a CPA or enrolled agent before setting your estimated payments, particularly in your first year of self-employment.