Every year, millions of taxpayers leave money on the table — not because they’re dishonest, but because they don’t know what they can deduct. The US tax code contains over a hundred deductions, credits, and adjustments, and even a few of the less obvious ones can add up to thousands of dollars. Here’s a practical guide to the ones people miss most often.

Deductions vs. credits: know the difference

A deduction reduces your taxable income. A credit reduces your actual tax bill, dollar for dollar. Credits are almost always more valuable than deductions of the same amount.

A $1,000 deduction in the 24% bracket saves you $240. A $1,000 credit saves you $1,000. Always claim every credit you qualify for first, then maximize deductions.

The deductions most people miss

1. Home office deduction. If you’re self-employed and use a portion of your home exclusively for business, you can deduct $5 per square foot (up to 300 sq ft) using the simplified method — that’s up to $1,500. The regular method requires more record-keeping but often yields a larger deduction based on actual expenses.

2. Student loan interest. You can deduct up to $2,500 of student loan interest per year, even if you don’t itemize. This is an above-the-line adjustment, meaning it reduces your adjusted gross income directly. Income phase-outs begin at $80,000 AGI (single) or $165,000 (married filing jointly).

3. State and local taxes (SALT). You can deduct state income taxes, local income taxes, and property taxes — but the total is capped at $10,000. If you live in a high-tax state, you almost certainly hit this cap, but many filers forget to include local taxes and smaller property tax payments.

4. Charitable contributions. Cash donations to qualified organizations are deductible up to 60% of AGI. Donations of clothing, furniture, and other goods are deductible at fair market value. Keep receipts and photos. Even small donations throughout the year add up.

5. Medical expenses. You can deduct unreimbursed medical expenses that exceed 7.5% of your AGI. If your AGI is $80,000, the threshold is $6,000. Any medical costs above that — insurance premiums, copays, prescriptions, dental work — are deductible. This is most useful in years with major procedures.

6. Educator expenses. Teachers can deduct up to $300 of out-of-pocket classroom expenses ($600 for married couples if both are educators) without itemizing.

Should you itemize or take the standard deduction?

For tax year 2026, the standard deduction is approximately:

Single: $15,000
Married filing jointly: $30,000
Head of household: $22,500

If your total itemizable deductions — mortgage interest, SALT (up to $10,000), charitable giving, and excess medical expenses — are less than the standard deduction, take the standard. About 90% of taxpayers do. But don’t assume — run the numbers using the Tax Refund Calculator to compare both scenarios.

How to calculate the actual value of a deduction

The value of a deduction depends on your marginal tax rate — the rate on your last dollar of income, not your average rate. The US uses progressive brackets:

Deduction value = Deduction amount × Marginal rate

A $3,000 deduction for someone in the 24% bracket is worth $720. The same deduction for someone in the 12% bracket is worth only $360. Use the Salary Calculator to determine your effective and marginal rates, and the Net Pay Calculator to see how deductions affect your take-home pay.

Commission and gig income deductions

If you earn commissions or freelance income, you have additional deduction opportunities that W-2 employees don’t:

Business mileage at the IRS rate (~67¢ per mile for 2026)
Business equipment (laptops, phones, software)
Professional development (courses, certifications, conferences)
Health insurance premiums (if self-employed)

The Commission Calculator can help you estimate your after-tax commission income when these deductions are factored in.

The bottom line

You don’t need a complex tax strategy to save money — you need to know what’s available and keep decent records throughout the year. A few hours of organization each quarter can mean hundreds or thousands of dollars back at tax time. When in doubt, calculate before you file.