A deduction reduces the income the IRS taxes you on

A tax deduction is an amount of money you subtract from your total income before calculating how much tax you owe. If you earned $50,000 and have $12,000 in deductions, the IRS taxes you on $38,000 instead. The deduction itself is not a refund or a credit — it straightforward shrinks the number that gets multiplied by your tax rate.

The larger your deductions, the smaller your taxable income, and the less tax you pay. A $1,000 deduction saves you money, but the exact amount depends on your tax bracket. Someone in the 22% bracket saves $220 on a $1,000 deduction; someone in the 12% bracket saves $120 on the same deduction.

Key Takeaways

  • A deduction reduces your taxable income, not your tax bill directly — the savings depend on your tax bracket.
  • The standard deduction is a fixed amount everyone can take; the itemized deduction route requires you to list specific expenses and usually only saves money if your total exceeds the standard amount.
  • Common deductions include mortgage interest, state and local taxes, charitable donations, and medical expenses above a certain threshold.
  • You choose either the standard deduction or itemized deductions on your tax return, not both.
  • Keeping receipts and records for deductible expenses is essential if you itemize, because the IRS can ask you to prove what you claimed.

Standard deduction versus itemized deductions

You have two paths on your tax return. The standard deduction is a flat amount set by the IRS each year that you can subtract from your income with no questions asked and no paperwork. For 2024, the standard deduction is $14,600 for single filers, $29,200 for married filing jointly, and $21,900 for head of household. These amounts change slightly each year.

The itemized deduction route means you add up specific expenses you paid during the year — mortgage interest, property taxes, charitable donations, medical bills — and subtract that total instead. You only benefit from itemizing if your total exceeds the standard deduction. If your itemized deductions add up to $18,000 and you are single, you itemize and deduct $18,000. If they add up to $12,000, you are better off taking the standard deduction of $14,600.

Most people take the standard deduction because it is simpler and because their actual deductible expenses do not add up to more. You cannot take both — you pick one or the other on your return.

Common expenses you can deduct if you itemize

Mortgage interest on your primary home and one vacation home is deductible, but only the interest portion, not the principal payment. Property taxes on real estate and vehicles are deductible, though there is a combined limit of $10,000 per year for state and local taxes (called the SALT cap). Charitable donations to may have access to organizations — churches, nonprofits, schools — count as deductions.

Medical and dental expenses are deductible, but only the amount that exceeds 7.5% of your adjusted gross income. If your income is $60,000, you can only deduct medical expenses above $4,500. Business expenses, if you are self-employed, are deductible. Student loan interest up to $2,500 per year is deductible even if you take the standard deduction (it is an "above-the-line" deduction).

Expenses that are not deductible include groceries, gas for commuting, most clothing, home repairs and maintenance, and life insurance premiums. The IRS publishes a full list in Publication 17, which you can find on irs.gov.

How deductions differ from credits and refunds

A tax credit is different from a deduction. A credit reduces your tax bill dollar-for-dollar. A $1,000 credit lowers your tax by exactly $1,000, regardless of your bracket. A $1,000 deduction lowers your taxable income by $1,000, which saves you money based on your tax rate — usually $120 to $370 depending on your bracket. Credits are more valuable than deductions.

A refund is money the IRS sends back to you because you overpaid during the year through withholding or estimated payments. It has nothing to do with deductions. You can have a large refund and zero deductions, or vice versa.

Record-keeping if you itemize

If you take the standard deduction, you do not need to keep receipts or records — the IRS does not ask for proof. If you itemize, you must keep documentation for every deduction you claim. This means receipts, bank statements, cancelled checks, or written acknowledgment from charities showing what you donated and when.

The IRS can audit your return up to three years after you file (or longer if they suspect fraud). If you cannot produce records for a deduction you claimed, the IRS will disallow it and you will owe back taxes plus interest and penalties. Keep your records in a folder or file for at least three years after filing.

When it makes sense to itemize

Itemizing makes sense if you own a home with a mortgage, pay significant state and local taxes, make large charitable donations, or have high medical expenses. A homeowner in a high-tax state might easily exceed the standard deduction. A renter with no mortgage and modest charitable giving will almost always come out ahead with the standard deduction.

You can use a straightforward worksheet to estimate: add up your expected mortgage interest, property taxes, charitable donations, and medical expenses above the 7.5% threshold. If the total is higher than the standard deduction for your filing status, itemize. If it is lower, take the standard deduction and move on.

Frequently Asked Questions

Can I deduct my home office if I work from home?

Yes, if you use part of your home exclusively for business. You can deduct either a percentage of your rent or mortgage interest, utilities, and home insurance (simplified method), or calculate the actual square footage of your office and deduct a matching percentage of home expenses (regular method). You must be self-employed or have a side business; W-2 employees cannot deduct a home office.

Do I have to deduct business expenses, or can I just take the standard deduction?

If you are self-employed, you must deduct your business expenses — you cannot take the standard deduction instead. Business expenses reduce your self-employment income and lower both income tax and self-employment tax. If you are a W-2 employee with a side business, you deduct business expenses on Schedule C and still take the standard deduction on your main return.

What happens if I claim a deduction the IRS does not allow?

If the IRS audits your return and disallows a deduction, you owe back taxes on the income you should not have deducted, plus interest calculated from the original due date. You may also owe penalties if the IRS determines the error was due to negligence or fraud. This is why keeping records is critical.

Can I deduct losses from my investments or gambling?

Investment losses can offset investment gains, and you can deduct up to $3,000 of net losses against other income in a single year. Gambling losses are deductible only up to the amount of gambling winnings you reported, and only if you itemize. You must keep records of both wins and losses.