Understanding Tax Deductions and How They Work

A tax deduction reduces your taxable income, which in turn lowers the amount of tax you owe. If you’re in the 22% tax bracket and claim a $1,000 deduction, you reduce your tax bill by $220. Deductions are not dollar-for-dollar reductions in your tax bill—that’s what a tax credit does—but they are still extremely valuable, especially when stacked together.

There are two types of deductions for individual filers: the standard deduction and itemized deductions. You must choose one or the other—you cannot take both. For most people, the standard deduction is higher, but if your individual deductible expenses add up to more than the standard amount, itemizing will save you more money.

The Standard Deduction for 2024

For the 2024 tax year, the standard deduction is:

  • Single filers: $14,600
  • Married filing jointly: $29,200
  • Head of household: $21,900

Taxpayers who are 65 or older or legally blind get an additional standard deduction of $1,550 (single) or $1,550 per qualifying person (married). The standard deduction is adjusted annually for inflation.

Above-the-Line Deductions (Adjustments to Income)

Certain deductions, known as “above-the-line” deductions or adjustments to gross income, can be taken regardless of whether you itemize. These reduce your Adjusted Gross Income (AGI), which is a key figure that affects your eligibility for many other tax benefits.

  • Traditional IRA contributions: Up to $7,000 ($8,000 if 50+) may be deductible depending on your income and whether you have a workplace retirement plan.
  • Student loan interest: Deduct up to $2,500 of student loan interest paid, subject to income phase-outs ($80,000–$95,000 for single filers, $165,000–$195,000 for married).
  • Educator expenses: Teachers and educators can deduct up to $300 for unreimbursed classroom supplies.
  • HSA contributions: Contributions to a Health Savings Account made outside of payroll are deductible up to the annual limit ($4,300 single / $8,550 family for 2025).
  • Alimony (pre-2019 agreements): Alimony payments under divorce agreements finalized before 2019 are deductible by the payer.
  • Self-employment taxes: Self-employed individuals can deduct half of their self-employment tax from gross income.
  • Self-employed health insurance: 100% of health insurance premiums paid for yourself and your family are deductible if you’re self-employed.
  • Self-employed retirement contributions: Contributions to SEP-IRA, SIMPLE IRA, or solo 401(k) plans are fully deductible.

Itemized Deductions: The Major Categories

If your itemized deductions exceed the standard deduction, filing Schedule A and itemizing will reduce your taxes more. Here are the primary itemized deductions available to individuals:

Mortgage Interest Deduction

You can deduct interest paid on a mortgage of up to $750,000 (for loans originated after December 15, 2017) for your primary and one secondary residence. For mortgages originated before that date, the limit is $1 million. This deduction can be worth thousands for homeowners, especially in the early years of a mortgage when interest payments are highest.

State and Local Taxes (SALT)

You can deduct state and local income taxes (or sales taxes in states with no income tax) plus property taxes, but the total SALT deduction is capped at $10,000 ($5,000 if married filing separately). This cap significantly limits the benefit for taxpayers in high-tax states.

Medical and Dental Expenses

You can deduct qualified medical and dental expenses that exceed 7.5% of your AGI. So if your AGI is $60,000, only expenses above $4,500 are deductible. Qualifying expenses include health insurance premiums (that you paid yourself), prescription medications, doctor and hospital visits, dental and vision care, and long-term care expenses.

Charitable Contributions

Cash donations to qualifying 501(c)(3) organizations are deductible up to 60% of your AGI. Donations of appreciated property (like stock) are deductible at fair market value up to 30% of AGI, and you also avoid capital gains tax on the appreciation—making this a particularly powerful strategy.

Always get a receipt for any donation over $250. For non-cash donations over $500, you must file Form 8283. For donations over $5,000, you generally need a qualified appraisal.

Casualty and Theft Losses

Starting in 2018, personal casualty and theft losses are only deductible if they result from a federally declared disaster. If you live in an area impacted by a declared disaster, you can deduct losses exceeding 10% of AGI (minus a $100 per-event floor).

Other Noteworthy Deductions

  • Gambling losses: Can be deducted up to the amount of gambling winnings you report. You must itemize to claim this.
  • Investment interest expense: Interest paid on money borrowed to purchase taxable investments is deductible up to your net investment income.
  • Impairment-related work expenses: Disabled individuals can deduct certain expenses that enable them to work.

Common Mistakes That Cost Taxpayers Deductions

Many taxpayers leave money on the table by failing to track deductible expenses throughout the year. Here are common mistakes to avoid:

  • Not keeping receipts for charitable donations
  • Forgetting to deduct state and local taxes paid
  • Missing the student loan interest deduction (it’s above-the-line—no need to itemize)
  • Overlooking HSA contributions made outside of payroll
  • Failing to compare total itemized deductions against the standard deduction

Record-Keeping Tips to Maximize Deductions

Good record-keeping is the foundation of maximizing deductions. Throughout the year: save all receipts for potential deductible expenses in a dedicated folder or app; track your mileage for charitable work and medical appointments; download or screenshot year-end statements from your lender, student loan servicer, and charity donation platform. These documents become the evidence you need if the IRS ever questions your deductions.

Should You Hire a Tax Professional?

If you have significant itemized deductions, self-employment income, rental property, or major life changes (marriage, divorce, home purchase), a CPA or enrolled agent can often find deductions you’d miss and ensure you’re compliant. Their fee is itself a deductible business expense if you’re self-employed. For simpler returns, free filing options through IRS Free File or tax software can handle standard and even moderately complex returns accurately.

Frequently Asked Questions

Should I take the standard deduction or itemize?

Take whichever is larger. Add up all your potential itemized deductions (mortgage interest, SALT up to $10,000, medical expenses above 7.5% of AGI, charitable contributions). If that total exceeds $14,600 (single) or $29,200 (married filing jointly), itemizing will save you more. Most Americans take the standard deduction.

Can I deduct my home office?

If you are self-employed and use part of your home regularly and exclusively for business, yes. Employees who work from home cannot claim the home office deduction on their federal return (this deduction was eliminated for employees from 2018 through 2025 under the Tax Cuts and Jobs Act).

Is the student loan interest deduction worth claiming?

Yes—it’s an above-the-line deduction worth up to $2,500 and requires no itemizing. If you paid interest on qualifying student loans and your modified AGI is below $95,000 (single) or $195,000 (married), claim it. It directly reduces your taxable income with no additional effort beyond entering the amount from your Form 1098-E.