A tax write-off reduces the income the IRS counts, which means you pay tax on less money

A tax write-off is an expense you subtract from your income before calculating how much tax you owe. If you earn $60,000 and have $10,000 in write-offs, the IRS treats you as if you earned $50,000. You then pay tax on that smaller number. The result is a smaller tax bill.

Write-offs work differently from tax credits. A credit directly reduces the tax you owe — a $1,000 credit cuts your bill by $1,000. A write-off reduces your income first, then the tax on that reduced income. If you are in the 22% tax bracket, a $1,000 write-off saves you about $220 in tax. The same $1,000 credit saves you the full $1,000.

The IRS allows write-offs only for certain kinds of spending. You cannot write off groceries or rent. You can write off business expenses if you are self-employed, medical bills above a threshold, charitable donations, and mortgage interest on your home loan. The rules are specific about what counts and what does not.

Key Takeaways

  • A write-off subtracts an expense from your income, lowering the amount the IRS taxes, rather than directly reducing your tax bill like a credit does.
  • You can only write off expenses the IRS has approved — business costs, medical bills above 7.5% of your income, charitable gifts, and mortgage interest are common examples.
  • You must choose between the standard deduction (a flat amount everyone can use) or itemizing deductions (adding up your individual write-offs), whichever is larger.
  • Self-employed people can write off home office space, vehicle mileage, supplies, and other business costs that employees cannot.
  • You need receipts, invoices, or bank statements to prove a write-off if the IRS asks — keeping records is as important as knowing which expenses count.

Standard deduction versus itemizing: which path saves you more

Every taxpayer gets to use either the standard deduction or itemized deductions, but not both. The standard deduction is a flat amount set by the IRS each year. For 2024, it is $14,600 for single filers and $29,200 for married couples filing jointly. You do not have to prove anything — you just claim it on your tax return.

Itemized deductions mean you add up all your individual write-offs — mortgage interest, property taxes, charitable donations, medical bills — and subtract that total instead. You only itemize if your total is larger than the standard deduction. Most people use the standard deduction because their write-offs do not add up to more.

The choice is straightforward: calculate both numbers, then use whichever is bigger. If your itemized deductions total $18,000 and the standard deduction is $14,600, you itemize. If they total $12,000, you use the standard deduction. You fill out Schedule A (Form 1040) if you itemize, or you just claim the standard deduction on your main return if you do not.

Common write-offs for employees and salaried workers

Most employees cannot write off job-related expenses anymore. The Tax Cuts and Jobs Act of 2017 suspended the deduction for unreimbursed employee expenses through 2025. That means if your employer does not pay for your work clothes, tools, or professional development, you cannot deduct those costs.

However, a few employee write-offs remain. If you are a teacher, you can deduct up to $300 per year for classroom supplies you buy yourself. If you are a member of the military reserves, you can deduct travel costs to and from duty. If you work from home and your employer does not reimburse you, you may be able to deduct a portion of your home office — but only if you are self-employed or a statutory employee, not a regular W-2 employee.

The main write-offs available to most employees are the ones that appear on your W-2 form already: your employer withheld taxes, and you may have contributed to a 401(k) or traditional IRA. Those reduce your taxable income automatically. Beyond that, employees rely on the standard deduction or itemized deductions like charitable gifts and mortgage interest.

Self-employed write-offs and business expenses

If you are self-employed, you can write off nearly any ordinary and necessary expense related to your business. This includes rent or mortgage interest for a home office, vehicle mileage (the IRS allows a standard mileage rate, which varies by year), office supplies, software subscriptions, professional fees, equipment, and insurance. You can also deduct a portion of your home utilities and internet if you use part of your home for business.

The key phrase is "ordinary and necessary." The IRS will not allow a write-off for a luxury vacation even if you call it a business trip. But a trip to meet a client, attend a conference, or research your market counts. Meals and entertainment during business travel are deductible, though the deduction is usually 50% of what you spend (100% for certain meals during 2023 and 2024).

Self-employed people file Schedule C (Form 1040) to report business income and expenses. You subtract your expenses from your revenue to find your profit, then pay income tax and self-employment tax on that profit. Keeping detailed records — receipts, invoices, mileage logs — is essential because the IRS audits self-employed returns more often than W-2 employee returns.

Medical and charitable write-offs

Medical expenses are deductible, but only the amount above 7.5% of your adjusted gross income (AGI). If your AGI is $60,000, you can only deduct medical costs above $4,500. That threshold is high enough that most people do not benefit unless they had a major illness, surgery, or ongoing treatment in the year. may have access to expenses include doctor visits, hospital stays, prescription drugs, dental work, vision care, and some medical equipment.

Charitable donations to may have access to organizations are fully deductible with no threshold. You can give to a registered nonprofit, religious organization, or public charity and write off the full amount. You need a receipt from the charity or a bank statement showing the donation. If you donate items like clothing or furniture, you need to estimate their fair market value and keep a list.

Both medical and charitable write-offs require itemizing. If your medical bills and charitable gifts combined do not exceed the standard deduction, you will not benefit from deducting them. This is why many people use the standard deduction instead — their write-offs straightforward do not add up to enough.

Mortgage interest and property tax deductions

If you own a home and have a mortgage, you can deduct the interest you pay on loans up to $750,000 of the home's purchase price. This is one of the largest write-offs available to homeowners. In the early years of a mortgage, most of your payment goes to interest, so the deduction is substantial. As years pass and you pay down the principal, the interest portion shrinks and so does the deduction.

Property taxes on your home are also deductible, but with a limit. The total of state and local taxes (SALT) you deduct — including property tax, income tax, and sales tax — cannot exceed $10,000 per year. In high-tax states, this cap means many homeowners cannot deduct all their property taxes.

These deductions only help if you itemize. Many homeowners, especially those with smaller mortgages or in lower-tax areas, find that the standard deduction is larger than their mortgage interest plus property taxes plus other itemized deductions combined. Running the numbers both ways on your tax return is the only way to know which path saves you more.

Keeping records and what the IRS requires

The IRS does not require you to attach receipts to your tax return, but you must keep them if you are audited. For write-offs, you need proof that the expense happened and that you paid it. A receipt from a store, an invoice from a service provider, a bank statement, or a credit card statement all count as proof.

For vehicle mileage, keep a log showing the date, destination, business purpose, and miles driven. For charitable donations over $250, you need a written acknowledgment from the charity. For medical expenses, keep the bills and explanation of benefits from your insurance company. For business expenses, organize receipts by category and keep them for at least three years — the IRS can audit returns going back that far in most cases.

If you are self-employed, the IRS expects you to keep records for every business expense you claim. A disorganized pile of receipts is not enough. You should track income and expenses in a ledger, spreadsheet, or accounting software. This protects you if you are audited and also helps you understand whether your business is actually profitable.

Frequently Asked Questions

Can I write off my car payment or car insurance?

No. Car payments are not deductible for personal use. Car insurance is also not deductible unless you are self-employed and use the vehicle for business — then you can deduct the business-use portion. If you are self-employed, you can deduct mileage instead of actual expenses, which is usually simpler.

What if I donate to a political campaign or church?

Political donations are never deductible. Donations to churches and religious organizations are deductible if the organization is registered as a may have access to charity. Most established churches may have access to, but you should ask the organization or check the IRS website to be sure.

Can I write off my home office if I am a W-2 employee working from home?

Not under current law. The deduction for unreimbursed employee expenses, including home office, is suspended through 2025. If you are self-employed or a statutory employee, you can deduct a home office using either the simplified method (multiply your office square footage by $5 per square foot) or actual expenses.

Do I need to itemize to write off student loan interest?

No. Student loan interest is an "above-the-line" deduction, meaning you can claim it whether you itemize or use the standard deduction. You can deduct up to $2,500 of student loan interest paid during the year, and you claim it on Form 1040 directly.

What happens if I claim a write-off I am not sure about?

If the IRS audits you and finds a write-off is not allowed, you will owe the tax you should have paid plus interest. If the error was unintentional, you usually do not face penalties. If the IRS thinks you were careless or dishonest, penalties can explore. When in doubt, do not claim the deduction or consult a tax professional before filing.