Freelance Self Employment Tax Formula
Learn how freelance self-employment tax, income tax, total tax and net income are estimated from revenue, expenses and tax rates.
This page explains the core math behind a freelance self-employment tax estimate. It shows how revenue, deductible expenses, additional deductions and user-entered tax rates combine to estimate total tax and after-tax income.
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Total Estimated Tax
Where:
First calculate net profit by subtracting business expenses from freelance revenue. Then subtract other deductions to get taxable income for income tax. Apply the income tax rate to taxable income, apply the self-employment tax rate to net profit, and add both taxes together.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| annualRevenue - Annual freelance revenue | Total freelance or self-employed income before expenses. | currency |
| businessExpenses - Annual business expenses | Deductible business costs subtracted from revenue to estimate net profit. | currency |
| otherDeductions - Other deductions | Additional deductions subtracted from net profit before estimating taxable income. | currency |
| incomeTaxRate - Estimated income tax rate | User-entered effective income tax rate used for the income tax estimate. | percent |
| selfEmploymentTaxRate - Self-employment tax rate | User-entered rate applied to net profit to estimate self-employment tax. | percent |
| taxPaidAlready - Tax already paid | Estimated tax payments or withholding already paid toward the total bill. | currency |
| netProfit - Net profit | Revenue minus deductible business expenses, not below zero. | currency |
| taxableIncome - Taxable income | Net profit minus other deductions, not below zero. | currency |
| totalTax - Total estimated tax | Combined income tax and self-employment tax. | currency |
Step-by-Step Calculation
Calculate net profit
Subtract deductible business expenses from total freelance revenue. If expenses exceed revenue, net profit is treated as zero for this estimate.
netProfit = max(annualRevenue - businessExpenses, 0)
Calculate taxable income
Reduce net profit by any additional deductions entered. The result is the amount used for the simplified income tax estimate.
taxableIncome = max(netProfit - otherDeductions, 0)
Estimate income tax
Apply the effective income tax rate to taxable income.
incomeTax = taxableIncome * (incomeTaxRate / 100)
Estimate self-employment tax
Apply the self-employment tax rate to net profit.
selfEmploymentTax = netProfit * (selfEmploymentTaxRate / 100)
Add taxes together
Combine the income tax estimate and the self-employment tax estimate.
totalTax = incomeTax + selfEmploymentTax
Subtract tax already paid
Subtract payments already made to estimate how much may still be due.
taxDue = max(totalTax - taxPaidAlready, 0)
Estimate after-tax income
Subtract business expenses and total estimated tax from gross freelance revenue to estimate remaining income.
netIncomeAfterTax = annualRevenue - businessExpenses - totalTax
Worked example: freelancer with moderate expenses
Net profit
max(60,000 - 12,000, 0)
$48,000
Taxable income
max(48,000 - 2,000, 0)
$46,000
Income tax
46,000 × 0.22
$10,120
Self-employment tax
48,000 × 0.153
$7,344
Total estimated tax
10,120 + 7,344
$17,464
Estimated tax still due
max(17,464 - 5,000, 0)
$12,464
Net income after tax
60,000 - 12,000 - 17,464
$30,536
Final Result
Estimated total tax: $17,464. Estimated tax still due: $12,464. Estimated net income after tax: $30,536.
Assumptions
- ✓The calculator uses the effective income tax rate entered rather than a full bracket-by-bracket tax system.
- ✓Business expenses and other deductions are assumed to be valid and already totaled correctly.
- ✓Self-employment tax is applied to net profit using the user-entered rate.
- ✓Tax credits, local taxes and filing-status-specific rules are not separately modeled unless reflected in the entered rates or deductions.
Limitations
- !Actual tax returns may use different rules, thresholds, caps or partial deductions that this estimate does not model.
- !The income tax estimate may differ from reality because it uses one overall rate instead of progressive brackets.
- !Results depend heavily on the accuracy of the revenue, expense and deduction inputs.
- !This estimate does not account for all country-specific or region-specific tax rules.
Common Mistakes to Avoid
Entering revenue after expenses instead of total revenue before expenses.
Using a marginal tax bracket as if it were an effective tax rate.
Forgetting to include business expenses, which can overstate both profit and tax.
Subtracting deductions twice by placing them in both business expenses and other deductions.
Ignoring tax already paid, which can make the remaining balance look too high.
Related Formulas
Frequently Asked Questions
What is the main formula for freelance self-employment tax?
The calculator estimates total tax by adding income tax on taxable income to self-employment tax on net profit.
Why is taxable income different from net profit?
Net profit is revenue minus business expenses, while taxable income further subtracts any other deductions entered into the calculator.
Why does the formula use max(..., 0)?
It prevents negative profit, taxable income or tax due from producing unrealistic negative tax estimates in this simplified model.
Does the formula use tax brackets?
No. It uses a single effective income tax rate entered by the user, so it is a simplified estimate.
Is self-employment tax calculated on revenue or profit?
In this calculator, self-employment tax is applied to net profit, which is revenue after business expenses.
How is tax still due calculated?
The calculator subtracts tax already paid from total estimated tax and floors the result at zero.
Ready to calculate your result?
Use the calculator to get instant results with your own inputs.