Your total gross income minus specific allowable "above-the-line" deductions (such as student loan interest, educator expenses, and 50% of self-employment tax). AGI is the baseline number the IRS uses to calculate your taxable income and determine credit eligibility.
Tax Filing Insight: Your AGI is calculated on line 11 of Form 1040. Prior year AGI is also used to verify your identity when e-filing your tax return.
A parallel tax system designed to ensure that high-income taxpayers who benefit from certain deductions and exemptions pay at least a minimum percentage of federal income tax.
Tax Filing Insight: AMT limits certain deductions like state and local taxes (SALT). Taxpayers calculate their tax under regular rules and AMT rules, paying whichever is higher.
An official revised tax return filed on IRS Form 1040-X to correct mistakes, report missed income, or claim overlooked deductions and tax credits on an originally filed return.
Tax Filing Insight: You generally have up to 3 years from the date you filed your original return (or 2 years from the date you paid the tax) to file Form 1040-X for a refund.
A mandatory 24% tax that payers must withhold from freelance, dividend, or contractor payments and remit directly to the IRS if the payee fails to provide a certified Form W-9 with a valid Taxpayer Identification Number (TIN).
Tax Filing Insight: Submitting an accurate, signed Form W-9 to your clients before receiving payment completely eliminates backup withholding.
The original investment amount in an asset (such as real estate, stocks, or business equipment), adjusted for depreciation, improvements, or reinvested dividends. Used to calculate taxable capital gain or deductible loss upon sale.
Tax Filing Insight: Keeping accurate receipts and purchase invoices is critical for establishing your cost basis and minimizing capital gains taxes.
A legal business structure where the corporation is taxed as a completely separate entity from its owners at the federal corporate tax rate (21%), potentially leading to "double taxation" on dividends.
Tax Filing Insight: Unlike S Corporations and sole proprietorships, C Corporations are not pass-through entities and do not qualify for the Section 199A QBI deduction.
A tax levied on the profit realized from the sale of a non-inventory asset (stocks, bonds, real estate). Short-term gains (held ≤ 1 year) are taxed as ordinary income; long-term gains (held > 1 year) enjoy preferential rates of 0%, 15%, or 20%.
Tax Filing Insight: Lottery winnings and gambling payouts are taxed as ordinary income, not capital gains.
A federal tax credit worth up to $2,000 per qualifying child under age 17, designed to reduce your dollar-for-dollar tax liability, with a refundable portion known as the Additional Child Tax Credit.
Tax Filing Insight: Unlike a tax deduction which reduces taxable income, a tax credit directly lowers your tax bill dollar-for-dollar.
An allowable dollar amount that reduces your adjusted gross income before calculating taxes. Taxpayers choose between the statutory flat Standard Deduction or Itemized Deductions (Schedule A) based on whichever yields greater tax savings.
Tax Filing Insight: For 2026, the standard deduction is $15,000 for Single filers and $30,000 for Married Filing Jointly.
An income tax deduction that allows business owners and 1099 freelancers to write off the cost of tangible business assets (computers, machinery, vehicles) over their useful statutory lifespan.
Tax Filing Insight: Section 179 allows qualifying business taxpayers to deduct 100% of the purchase price of eligible business equipment in the very first year.
A business entity (typically a Single-Member LLC) that the IRS ignores for federal income tax purposes. The LLC profits and losses pass directly to the owner’s individual Form 1040 (Schedule C).
Tax Filing Insight: On Form W-9 Line 1, a single-member LLC owner enters their individual name, and puts the LLC name on Line 2.
A refundable federal tax credit targeted at low-to-moderate-income working individuals and families. Because it is refundable, it can result in a direct tax refund even if you owe $0 in income tax.
Tax Filing Insight: The IRS holds tax refunds claiming EITC under the PATH Act until mid-February to verify eligibility.
A unique 9-digit identification number (XX-XXXXXXX) issued for free by the IRS to identify businesses, corporations, partnerships, and sole proprietors for tax reporting.
Tax Filing Insight: Using an EIN on Form W-9 instead of your personal Social Security Number protects you against identity theft.
Quarterly tax payments required from freelancers, independent contractors, and investors whose income is not subject to employer payroll tax withholding.
Tax Filing Insight: Estimated tax vouchers are due on April 15 (Q1), June 15 (Q2), September 15 (Q3), and January 15 (Q4).
A mandatory electronic filing required by the U.S. Treasury for citizens, residents, and entities holding a financial interest in or signature authority over foreign financial accounts whose total aggregate value exceeds $10,000 at any time during the calendar year.
Tax Filing Insight: FBAR is filed with FinCEN by April 15 with an automatic extension to October 15.
The Federal Insurance Contributions Act mandatory payroll tax consisting of a 6.2% Social Security tax and a 1.45% Medicare tax deducted from employee wages, matched equally by employers (7.65% employee + 7.65% employer = 15.3% total).
Tax Filing Insight: 1099 independent contractors pay both halves (15.3%) through the Self-Employment Tax.
Your category for filing federal income taxes: Single, Married Filing Jointly, Married Filing Separately, Head of Household, or Qualifying Surviving Spouse. It determines standard deduction amounts and tax bracket boundaries.
Tax Filing Insight: Head of Household filing status provides broader tax brackets and higher deductions than Single status for unmarried individuals supporting dependents.
The official statutory tax form used by personal taxpayers to report annual income, calculate tax liability, claim deductions and credits, and determine refund or amount owed to the IRS.
Tax Filing Insight: Form 1040 is supplemented by Schedules 1, 2, 3, Schedule C (Business), and Schedule SE (Self-Employment).
An IRS information return issued by third-party settlement organizations (PayPal, Venmo, Stripe, Square, eBay, Airbnb) reporting gross payment transactions processed for goods and services.
Tax Filing Insight: Gross amounts on Form 1099-K do not account for refunds, fees, or cost of goods sold. Reconcile these on Schedule C.
An information return used to report miscellaneous payments such as rent ($600+), prizes and awards, medical payments, and attorney proceeds (distinct from non-employee contractor compensation on Form 1099-NEC).
Tax Filing Insight: Independent contractor payments moved from 1099-MISC Box 7 to Form 1099-NEC.
The IRS information form used by businesses to report non-employee compensation of $600 or more paid to independent contractors, gig workers, and sole proprietors during the tax year.
Tax Filing Insight: Form 1099-NEC is sent to payees and the IRS by January 31 following the tax year.
An IRS form submitted by taxpayers to request an automatic 6-month extension of time to file their Form 1040 federal tax return, extending the filing deadline from April 15 to October 15.
Tax Filing Insight: Form 4868 extends the time to file your paperwork, but does not extend the deadline to pay taxes owed. Taxes must still be paid by April 15.
The quarterly federal tax return filed by employers to report income taxes, Social Security tax, and Medicare tax withheld from employee paychecks, plus the employer’s matching FICA portion.
Tax Filing Insight: Form 941 is due on the last day of the month following the end of each calendar quarter (April 30, July 31, October 31, January 31).
The official Wage and Tax Statement provided annually by employers to employees and the Social Security Administration, summarizing total annual earnings, federal income tax withheld, and FICA taxes.
Tax Filing Insight: Employees use Box 1 (Wages) and Box 2 (Federal withholding) to complete their Form 1040 tax returns.
The Employee’s Withholding Certificate completed by employees to instruct their employer on how much federal income tax to withhold from each paycheck.
Tax Filing Insight: You should submit a revised Form W-4 whenever you experience a major life event like marriage, childbirth, or second job income.
The Request for Taxpayer Identification Number and Certification used by businesses to obtain the legal name, tax classification, address, and TIN/EIN of contractors before issuing payments.
Tax Filing Insight: Form W-9 is retained by the requester and is never sent directly to the IRS.
Your total compensation from all sources (wages, contractor payments, interest, dividends, rental income) before taking out any taxes, deductions, or business expenses.
Tax Filing Insight: Your net take-home pay is calculated by subtracting payroll taxes, income tax withholding, and benefit deductions from your gross earnings.
An advantageous tax filing status for unmarried taxpayers who pay more than 50% of the cost of keeping up a home for themselves and a qualifying dependent child or relative.
Tax Filing Insight: HOH filers receive a significantly higher standard deduction than Single filers and broader tax brackets.
A tax-advantaged savings account paired with a High Deductible Health Plan (HDHP). Offers "triple tax advantages": contributions are 100% tax-deductible, growth is tax-free, and withdrawals for medical expenses are tax-free.
Tax Filing Insight: HSA funds roll over indefinitely each year with no "use-it-or-lose-it" restriction.
A valuable tax write-off for 1099 contractors and self-employed individuals who use a portion of their home regularly and exclusively as their principal place of business. Calculated using either the simplified method ($5 per square foot up to 300 sq ft) or actual square footage allocation of rent, utilities, and internet.
Tax Filing Insight: The dedicated workspace must meet the strict "exclusive and regular use" test.
A self-employed professional who provides services to clients under contract. Unlike W-2 employees, independent contractors control their work methods, provide their own equipment, and pay self-employment tax.
Tax Filing Insight: Contractors fill out Form W-9 instead of Form W-4 and receive Form 1099-NEC instead of Form W-2.
A 9-digit tax processing number issued by the IRS for foreign nationals, non-resident aliens, and individuals who are required to file a U.S. tax return but are not eligible for a Social Security Number (SSN).
Tax Filing Insight: An ITIN begins with the number "9" and is formatted like an SSN (9XX-XX-XXXX).
Individual eligible expenses (mortgage interest, charitable donations, state/local taxes up to $10,000, unreimbursed medical expenses over 7.5% AGI) claimed on Form 1040 Schedule A instead of the standard deduction.
Tax Filing Insight: You should only itemize deductions if your total deductible expenses exceed the standard deduction threshold.
A legal business entity that provides personal asset liability protection for its members while offering flexible pass-through tax status as a sole proprietorship, partnership, or S Corporation.
Tax Filing Insight: A single-member LLC checks the "Individual / sole proprietor or single-member LLC" box on Form W-9.
A one-time cash settlement option for lottery winners (typically ~60% of the advertised jackpot), subject to an immediate 24% mandatory federal withholding plus top marginal bracket settlement at 37%.
Tax Filing Insight: In 0% tax states like California, Florida, or Texas, winners owe $0 in state income tax on lottery prizes.
The tax percentage applied to the very last dollar of your taxable income. Under the U.S. progressive bracket system, entering a higher tax bracket only taxes the portion of income above the bracket threshold at that higher rate.
Tax Filing Insight: Your marginal rate is different from your effective rate (your total tax divided by total gross income).
A federal payroll tax of 2.9% (1.45% employee + 1.45% employer) on all earned wage and self-employment income with no annual wage ceiling. An Additional Medicare Tax of 0.9% applies to high earners earning over $200,000 (Single) or $250,000 (Married).
Tax Filing Insight: Unlike Social Security tax, Medicare tax has no maximum wage cap.
An IRS-approved cents-per-mile deduction for business miles driven by self-employed individuals and freelancers in lieu of tracking actual vehicle gas, depreciation, and repair expenses.
Tax Filing Insight: The standard business mileage rate covers gas, insurance, maintenance, and vehicle wear.
Your actual take-home earnings remaining after subtracting all mandatory federal, state, and local income taxes, FICA payroll taxes, and voluntary pre-tax deductions.
Tax Filing Insight: For businesses, net income is gross revenue minus allowable business operating expenses and cost of goods sold.
The statutory connection between a business/remote contractor and a state tax jurisdiction that obligates the taxpayer to collect sales tax or file a state income tax return in that state.
Tax Filing Insight: Performing remote work physically in another state can trigger state income tax withholding obligations.
A business structure (sole proprietorship, partnership, LLC, S Corporation) that does not pay corporate income taxes at the entity level. Business net profits pass directly to the owners’ personal tax returns.
Tax Filing Insight: Pass-through businesses may qualify for the 20% Section 199A Qualified Business Income (QBI) deduction.
A valuable federal tax deduction enacted under the TCJA that allows eligible sole proprietors, LLC owners, and S Corporation shareholders to deduct up to 20% of their net pass-through qualified business profit from income taxes.
Tax Filing Insight: The QBI deduction reduces federal income taxes, but does not reduce your 15.3% Self-Employment tax.
Four statutory tax installments paid annually to the IRS (and state departments of revenue) by self-employed workers and freelancers to satisfy their pay-as-you-go tax obligations without underpayment penalties.
Tax Filing Insight: To avoid underpayment penalties, utilize the "Safe Harbor" rule by paying at least 90% of your current year tax liability or 100% of your prior year tax.
A formal tax agreement between neighboring states allowing commuters who live in one state and work across state lines in another to pay income taxes solely to their resident home state.
Tax Filing Insight: Reciprocity prevents double withholding and saves employees from needing to file non-resident tax returns.
A tax election made with IRS Form 2553 that allows an LLC or corporation to distribute profits as a mix of W-2 salary (subject to FICA) and shareholder distributions (free of 15.3% self-employment tax).
Tax Filing Insight: S Corp owners must pay themselves a "reasonable W-2 salary" for their services before taking non-taxed distributions.
An itemized tax deduction allowing taxpayers to write off state and local income taxes (or sales taxes) plus local real estate and property taxes, subject to a statutory $10,000 maximum annual cap.
Tax Filing Insight: High-tax states like CA, NY, and NJ have enacted Pass-Through Entity (PTE) tax workarounds for business owners to bypass the $10,000 SALT cap.
The primary IRS tax form used by sole proprietors, independent contractors, and single-member LLCs to report gross business revenue, itemize business expenses, and calculate net taxable profit.
Tax Filing Insight: Your net profit from Schedule C Line 31 transfers to Form 1040 and Schedule SE to calculate self-employment tax.
A valuable 100% above-the-line deduction allowing self-employed individuals, freelancers, and single-member LLCs to write off health, dental, and qualifying long-term care insurance premiums for themselves and their families.
Tax Filing Insight: The deduction cannot exceed your net self-employment business profit for the year.
A combined 15.3% federal tax consisting of 12.4% Social Security (on net earnings up to $176,100) and 2.9% Medicare (on all net earnings) paid by independent contractors and sole proprietors.
Tax Filing Insight: The IRS allows you to deduct 50% of your self-employment tax as an above-the-line deduction on Form 1040.
A statutory payroll tax funding the federal Old-Age, Survivors, and Disability Insurance (OASDI) program, levied on earned wages up to an annual statutory wage cap ($176,100 for 2025/2026).
Tax Filing Insight: Earnings exceeding the annual wage cap are taxed at 0% for Social Security.
High-limit retirement savings vehicles designed exclusively for sole proprietors, freelancers, and small business owners with no full-time employees, allowing massive pre-tax deductions that slash taxable income.
Tax Filing Insight: A Solo 401(k) allows you to contribute both as an "employee" (up to $23,500) and as the "employer" (up to 25% of net profit), up to the annual combined maximum.
A statutory base dollar amount that the IRS permits taxpayers to subtract from their income with no receipts or record-keeping required, indexed annually for inflation.
Tax Filing Insight: For 2026: Single ($15,000), Married Filing Jointly ($30,000), and Head of Household ($22,500).
An above-the-line federal tax deduction that allows eligible taxpayers to deduct up to $2,500 of interest paid during the year on qualified higher education student loans, even if they take the standard deduction.
Tax Filing Insight: Reported to you by your loan servicer on IRS Form 1098-E.
A statutory range of taxable income taxed at a specific marginal tax rate. The federal tax code has 7 income tax brackets: 10%, 12%, 22%, 24%, 32%, 35%, and 37%.
Tax Filing Insight: Moving into a higher bracket never reduces your take-home pay because only the income inside that higher bracket is taxed at the higher rate.
A critical distinction: A Tax Deduction reduces the amount of income subject to tax (saving you a percentage based on your bracket), while a Tax Credit directly reduces your tax liability dollar-for-dollar.
Tax Filing Insight: A $1,000 tax credit saves you $1,000; a $1,000 tax deduction in the 22% bracket saves you $220.
An umbrella term for official 9-digit identification numbers used by the IRS to administer tax laws, including Social Security Numbers (SSN), Employer Identification Numbers (EIN), and Individual Taxpayer Identification Numbers (ITIN).
Tax Filing Insight: Entering a valid TIN on Form W-9 prevents 24% backup withholding.
A continuous legal process where the IRS orders an employer to withhold a substantial portion of an employee’s paycheck to satisfy unpaid federal back taxes.
Tax Filing Insight: The IRS must send a Final Notice of Intent to Levy (Letter 1058 / LT11) at least 30 days before initiating wage garnishment.
The amount of employee wages withheld by an employer from every paycheck and forwarded to the IRS and state treasury as prepayment of the employee’s annual income taxes.
Tax Filing Insight: Adjust your Form W-4 to ensure your withholding matches your annual liability and avoid owing large balances in April.
Generate IRS Form W-9 (Rev. March 2024) PDFs, estimate quarterly 1040-ES taxes, and model take-home pay with our free tax utilities.