What is Income Tax?

**Income tax is a tax levied by federal, state, and sometimes local governments on the earnings of individuals and businesses, calculated as a percentage of taxable income.** For freelancers and self-employed individuals in the United States, income tax is one of two major taxes on business earnings -- the other being the self-employment tax that covers Social Security and Medicare contributions. The United States federal income tax system is progressive, meaning higher levels of income are taxed at higher rates. Tax rates are applied in brackets: the first portion of taxable income is taxed at the lowest rate, subsequent portions at progressively higher rates. As of 2024, the federal income tax brackets range from 10 percent on the first dollars of taxable income to 37 percent on income above approximately $609,350 for single filers. For freelancers, income tax is particularly important to understand because unlike employees -- who have taxes automatically withheld from each paycheck -- self-employed individuals receive their full client payments and must proactively set aside and pay income tax themselves. Failing to plan for income tax is one of the most common financial mistakes among new freelancers, often resulting in an unexpectedly large tax bill when April arrives. Federal income tax is separate from self-employment tax. Freelancers pay both: self-employment tax (15.3 percent) on net self-employment income up to the Social Security wage base, plus federal income tax at their applicable bracket rate on all taxable income. State income taxes add a further layer, with rates ranging from zero (in states like Texas and Florida) to over 13 percent in California. Understanding all three layers is essential for accurate tax planning.

The income tax process for freelancers follows a distinct path from that of employees. Rather than having taxes automatically deducted from a paycheck, freelancers must calculate, set aside, and pay their own taxes throughout the year. Here is how the process unfolds: At the start of each year (or when your business situation changes), estimate your expected annual net income from freelancing. Apply your expected marginal tax brackets to estimate federal income tax owed. Add your estimated self-employment tax. Subtract any expected credits. This gives you an estimated annual tax liability. Divide that annual liability by four and pay those quarterly installments to the IRS by the due dates: April 15, June 15, September 15, and January 15. These are called estimated tax payments. If you expect to owe $5,000 or more in taxes for the year and your withholding does not cover at least 90 percent of the current year's tax or 100 percent of the prior year's tax (whichever is smaller), you must make these quarterly payments or face an underpayment penalty. At year-end, you file your annual return (Form 1040 with Schedule C and Schedule SE for self-employment). Your actual tax liability is calculated based on true annual income and deductions. Any overpayment from quarterly installments results in a refund; any underpayment is due when you file. State income tax follows a similar structure in states that impose it. Most states require quarterly estimated payments from self-employed individuals as well. Check your state's department of revenue website for specific due dates and calculation methods, as they vary.

The income tax mechanics differ significantly between employees and freelancers, and the differences go beyond just the paperwork. For an employee, the employer withholds federal and state income tax from every paycheck based on the W-4 form the employee filed. The employee pays only the employee share of FICA taxes (7.65 percent for Social Security and Medicare). If the employer withholds correctly, the employee owes little or nothing when filing their annual return -- the withholding system handles everything automatically. For a freelancer, all client payments arrive gross -- no withholding, no automatic deduction. The freelancer must calculate their own tax obligation and set aside funds proactively. In addition to income tax at the same bracket rates as employees, freelancers pay self-employment tax (15.3 percent) representing both employee and employer portions of Social Security and Medicare. The tax-planning implication is significant. A freelancer earning $80,000 in net self-employment income faces self-employment tax of approximately $11,304 plus federal income tax. An employee earning $80,000 in salary has significantly lower total tax because the employer covers half of the FICA obligation. This structural difference is why freelancers must price their services higher than equivalent employee salaries to achieve the same after-tax income. However, freelancers have tax advantages employees typically lack: they can deduct business expenses on Schedule C, claim the home office deduction, deduct health insurance premiums, and make tax-deductible retirement contributions through SEP-IRA or solo 401(k) at much higher limits than employees. These deductions can partially or fully offset the self-employment tax disadvantage for well-organized freelancers.

Income tax and self-employment tax are two distinct taxes that freelancers must both pay, and confusing them leads to serious underestimation of the total tax burden. **Income tax** is calculated on taxable income after deductions. It funds general federal spending. The rates are progressive (10 percent to 37 percent federally). Everyone with taxable income pays income tax. **Self-employment tax** is calculated on net self-employment earnings (roughly 92.35 percent of net profit from Schedule C to account for the deduction of half of SE tax). It is a flat 15.3 percent up to the Social Security wage base ($168,600 in 2024), then 2.9 percent above that. It funds Social Security and Medicare specifically. Only self-employed individuals pay this directly; employees pay 7.65 percent with employers matching it. Both taxes apply to freelancers, and both must be planned for. A freelancer with $50,000 in net self-employment income might owe roughly $7,065 in self-employment tax (15.3 percent of $46,175, which is 92.35 percent of $50,000) plus federal income tax on that net income minus deductions. The combined burden for many freelancers in the $50,000 to $100,000 net income range is roughly 30 to 40 percent of net income when federal, SE, and state taxes are combined. The silver lining: you can deduct one-half of self-employment tax paid as an above-the-line deduction from gross income. This reduces your AGI and your income tax, partially offsetting the SE tax burden. Work with a tax professional to ensure this deduction is properly captured.

Estimating your income tax accurately as a freelancer requires a multi-step process that accounts for all relevant taxes, deductions, and credits. **Step 1: Estimate annual net profit.** Start with expected gross business income and subtract expected business deductions to arrive at estimated net profit from Schedule C. **Step 2: Calculate self-employment tax.** Multiply net profit by 92.35 percent, then multiply by 15.3 percent (up to the wage base). The result is your estimated SE tax obligation. **Step 3: Subtract half of SE tax from gross income.** This above-the-line deduction reduces your adjusted gross income. **Step 4: Apply additional deductions.** Subtract the QBI deduction (up to 20 percent of qualified business income), standard deduction or itemized deductions, and any other above-the-line deductions. **Step 5: Apply federal tax brackets.** Apply the progressive federal rates to your estimated taxable income to calculate federal income tax owed. **Step 6: Add state income tax.** Look up your state's tax rate and calculate estimated state income tax. **Step 7: Divide by four for quarterly payments.** Pay one-quarter of your estimated total annual tax (federal + SE + state) by each quarterly deadline. **Step 8: Revisit estimates each quarter.** If your income changes significantly, update your estimates and adjust quarterly payments accordingly to avoid underpayment penalties.

The foundation of accurate income tax preparation is accurate income records. When every client payment flows through a professional invoicing system like Eonebill.ai, you have a complete, organized record of all business income throughout the year -- which is exactly what you or your accountant needs to calculate accurate income tax liability. The free invoice generator at /free-tools/invoice-generator creates a professional record for every client transaction. Whether you send 5 invoices per year or 50, each invoice serves as documentation of income received -- the raw material for your Schedule C gross income calculation. Freelancers using Eonebill's Pro plan at $19 per month have access to organized invoice history and payment records, making year-end tax preparation faster and reducing the stress of reconstructing a year's worth of income data in April. Visit /pricing for full plan details. Accurate income records also protect you in the event of an audit. If the IRS questions the income figures on your Schedule C, a complete record of professional invoices with dates and amounts provides clear documentation. Informal payment records -- screenshots of bank deposits, cash logs -- are far harder to defend than a professional invoicing system's complete history.

1. **Not setting aside taxes from each payment.** Many new freelancers spend their full client payments and are shocked to find they owe 30 percent or more in taxes at year-end. Open a dedicated tax savings account and transfer 25 to 30 percent of every client payment into it immediately upon receipt. 2. **Missing quarterly estimated tax deadlines.** The IRS charges an underpayment penalty for freelancers who do not make adequate quarterly payments. Set calendar reminders for each due date and pay even if your estimates are rough -- paying something is better than paying nothing. 3. **Underestimating the combined tax burden.** Many freelancers calculate only income tax and forget self-employment tax, leading to significant underpayment. Remember that SE tax (15.3 percent) adds a substantial layer on top of income tax. 4. **Forgetting deductions that reduce taxable income.** Failing to claim all eligible deductions -- especially home office, retirement contributions, and health insurance premiums -- results in overpaying taxes. Track deductible expenses throughout the year. 5. **Filing taxes without professional help when business is complex.** As freelance income grows and business structure becomes more complex, the cost of a CPA typically becomes negligible compared to the tax savings they identify. Trying to optimize a complex self-employment tax situation without professional guidance often costs more in missed deductions than the CPA fee.

Income tax connects to the full ecosystem of freelancer tax obligations: **Self-Employed Person** -- The tax classification that determines how income tax interacts with self-employment tax. See /glossary/self-employed-person. **Tax Bracket** -- The progressive rate structure through which income tax is calculated. Understanding your bracket helps you estimate obligations and plan strategically. See /glossary/tax-bracket. **Deduction** -- Business deductions reduce taxable income and therefore reduce income tax owed. See /glossary/deduction. **Gross Income** -- The starting point before deductions, which feeds into income tax calculation. See /glossary/gross-income. **W-2 Form** -- The employee income document, contrasted with the 1099-NEC that freelancers receive. Understanding the difference clarifies how income tax withholding differs between the two. See /glossary/w-2-form.