To estimate federal tax on a real estate commission, run the net profit through two calculations: self-employment tax at 15.3% on 92.35% of earnings, then federal income tax at marginal rates from 10% to 37% on what remains after deductions. A real estate commission tax calculator built around those two layers typically produces an effective federal rate between 25% and 40%, depending on total earnings, deductions, and filing status. The steps below walk through the same math a calculator uses, so you can run the numbers on your own commissions and see where each dollar goes.
Start With Net Profit, Not Gross Commission
Every calculation begins with net profit from Schedule C, not the gross figure on your 1099-NEC. Your brokerage reports the full commission paid to you, but that number does not reflect the broker’s split or any business expenses.1Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) Subtract the split and all legitimate business costs first. What’s left is the number that feeds both tax calculations.
Two deductions carry weight for most agents. The 2026 IRS standard mileage rate for business use is 72.5 cents per mile, covering cars, vans, pickups, and panel trucks, including fully electric and hybrid vehicles.2Internal Revenue Service. IRS Sets 2026 Business Standard Mileage Rate at 72.5 Cents Per Mile An agent driving 15,000 business miles deducts $10,875. The simplified home office method allows $5 per square foot up to 300 square feet, capped at $1,500 a year, for space used regularly and exclusively for business.3Internal Revenue Service. Simplified Option for Home Office Deduction Both reduce net profit before either tax layer is applied, so they lower self-employment tax and income tax at the same time.
Calculate Self-Employment Tax
Self-employment tax covers both the employer and employee shares of Social Security and Medicare that a W-2 job would split. The combined rate is 15.3%, broken into 12.4% for Social Security and 2.9% for Medicare.4Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)5Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax
The rate does not hit your full net profit. Multiply net earnings by 92.35% first, then apply 15.3% to that base.6Internal Revenue Service. Topic No. 554, Self-Employment Tax Schedule SE handles this on Line 4a by multiplying net earnings by 0.9235.7Internal Revenue Service. Schedule SE (Form 1040) – Self-Employment Tax The adjustment mirrors the tax break W-2 employees get because an employer’s FICA share isn’t part of their taxable wages.
For 2026, only the first $184,500 of net self-employment earnings is subject to the 12.4% Social Security piece.8Social Security Administration. Contribution and Benefit Base Above that, only the 2.9% Medicare portion continues. Most agents fall below the cap, so the full 15.3% applies to 92.35% of net profit.
Half of the self-employment tax you calculate is then deductible when figuring adjusted gross income.6Internal Revenue Service. Topic No. 554, Self-Employment Tax It reduces the income subject to federal income tax but does not reduce the self-employment tax itself.
Calculate Federal Income Tax
The income tax layer runs on adjusted gross income after subtracting your standard or itemized deduction. For 2026, the standard deduction is $16,100 for single filers and $32,200 for married couples filing jointly.9Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
The 2026 federal income tax brackets for single filers:
- 10%: $0 to $11,925
- 12%: $11,926 to $48,475
- 22%: $48,476 to $103,350
- 24%: $103,351 to $197,300
- 32%: $197,301 to $250,525
- 35%: $250,526 to $626,350
- 37%: $626,351 and above
These are marginal rates. Only the income falling inside each bracket is taxed at that bracket’s rate.10Internal Revenue Service. Federal Income Tax Rates and Brackets An agent with $80,000 in taxable income pays 10% on the first $11,925, 12% on the next slice, and 22% only on the portion above $48,475.
Qualified Business Income Deduction
Section 199A lets eligible self-employed individuals deduct up to 20% of qualified business income.11Internal Revenue Service. Qualified Business Income Deduction The deduction was extended through 2026 under recent federal tax legislation.9Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Real estate brokerage is not classified as a specified service trade or business, so agents generally qualify for the full deduction while taxable income stays below the phase-out. For 2026, the phase-out begins at roughly $201,750 for single filers and $403,500 for joint filers.
Below those thresholds, the calculation is 20% of net business profit, limited to 20% of overall taxable income. It’s a below-the-line deduction that stacks with the standard or itemized deduction and reduces only the income tax portion, not self-employment tax.
Worked Example at $100,000 Net Profit
Take a single agent with $100,000 in net profit on Schedule C after the broker’s split and all business expenses.
Self-employment tax:
- SE tax base: $100,000 × 92.35% = $92,350
- SE tax owed: $92,350 × 15.3% = $14,130
- Half-SE deduction from AGI: $7,065
Federal income tax:
- Adjusted gross income: $100,000 − $7,065 = $92,935
- Standard deduction (single): $16,100
- Taxable income: $92,935 − $16,100 = $76,835
- Federal income tax: approximately $11,818 using the marginal brackets
Total federal tax lands near $25,948, leaving roughly $74,052 after federal obligations. State income tax, where it applies, comes off after that; rates range from 0% in states without an income tax to over 13% in the highest-tax states. Applying the QBI deduction would cut the income tax portion by several thousand dollars more.
Additional Medicare Tax at Higher Income
Self-employment income above $200,000 for single filers or $250,000 for married filing jointly owes an extra 0.9% Additional Medicare Tax on the amount over the threshold.12Internal Revenue Service. Topic No. 560, Additional Medicare Tax This is on top of the 2.9% Medicare piece already inside the 15.3% self-employment tax. A single agent with $300,000 in net self-employment earnings owes the surtax on $100,000, which comes to $900. If you also have W-2 wages, the threshold is reduced by your Medicare wages, so the surtax can start at a lower level of self-employment income than the raw numbers suggest.13Internal Revenue Service. Instructions for Form 8959, Additional Medicare Tax
Pay It Quarterly to Avoid Penalties
Because no one withholds from your commissions, the IRS expects four estimated payments a year using Form 1040-ES.14Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals The 2026 deadlines:
- April 15, 2026 for January through March income
- June 15, 2026 for April and May income
- September 15, 2026 for June through August income
- January 15, 2027 for September through December income
If a due date lands on a weekend or legal holiday, the payment is due the next business day.15Internal Revenue Service. Estimated Tax
Underpayment penalties are calculated from the amount owed, how late it is, and the IRS’s quarterly interest rate.16Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty You avoid the penalty entirely if any of these apply:
- You owe less than $1,000 after subtracting withholdings and credits.
- You paid at least 90% of your current-year tax liability through estimated payments.
- You paid at least 100% of last year’s total tax. If your prior-year AGI exceeded $150,000 ($75,000 if married filing separately), the threshold rises to 110% of last year’s tax.
The prior-year safe harbor is useful when income swings. After a strong year followed by a slower one, basing payments on the previous year’s liability protects you from penalties even when the current-year estimate falls short.