Most filers claim the obvious deductions and stop there, leaving money on the table every year. Here are ten that get missed most often, whether you file with software, a preparer, or on your own — with the actual 2026 dollar figures so you can tell right away if one applies to you.
- State sales tax instead of state income tax. If you itemize, you can choose to deduct state and local sales tax instead of income tax — which helps if you made a big purchase (car, boat, home renovation) or live in a state with no income tax. You can’t deduct both; the IRS makes you pick whichever is larger, and their optional sales tax tables plus your big-ticket receipts usually beat guessing.
- Student loan interest. Up to $2,500 in student loan interest is deductible above the line — no itemizing required — even if a parent isn’t the one who signed the loan, as long as they’re legally obligated to repay it. For 2026, the deduction phases out between $85,000–$100,000 of MAGI for single filers and $175,000–$205,000 for married filing jointly. Married filing separately can’t claim it at all, at any income.
- HSA contributions made outside payroll. Contributions made directly to your HSA provider (rather than through payroll deduction) are still deductible above the line if you have a qualifying high-deductible health plan — people who switch jobs or funded an HSA before enrolling in payroll deductions often forget this counts too.
- Self-employed health insurance premiums. Self-employed filers can often deduct 100% of health insurance premiums paid for themselves, a spouse, and dependents, above the line — a deduction that’s easy to miss if you’re used to a W-2 job where this was handled pre-tax through payroll.
- Charitable mileage and out-of-pocket costs. Miles driven for volunteer work are deductible at 14¢/mile (a rate set by statute, not adjusted annually like the business rate), and unreimbursed supplies you personally buy for a qualified charity count too — not just cash and check donations.
- The retirement Saver’s Credit. Lower and middle-income filers who contribute to an IRA or employer retirement plan may qualify for a credit worth 10%, 20%, or 50% of up to $2,000 in contributions ($4,000 for joint filers), on top of any deduction from the contribution itself. For 2026, the top 50% tier applies up to $24,250 AGI (single), $36,375 (head of household), or $48,500 (married filing jointly) — and it’s a credit, not a deduction, so it reduces your tax bill dollar-for-dollar.
- Home office deduction for the self-employed. Available to self-employed filers with a dedicated workspace used regularly and exclusively for business, but frequently overlooked by people who assume it no longer exists after the 2018 tax law changes eliminated it for W-2 employees. It was never eliminated for the self-employed.
- Educator expenses — but the rules changed for 2026. For 2025, eligible teachers could deduct up to $300 of out-of-pocket classroom supplies above the line, no itemizing needed. Starting in 2026, the 2025 One Big Beautiful Bill Act moves this deduction to Schedule A as an itemized deduction and removes the $300 cap — a bigger potential write-off for teachers who spend heavily on their classrooms, but only if you itemize. If you take the standard deduction, this one no longer helps you at all.
- Medical expenses above the threshold. Filers with high medical costs forget that once expenses exceed 7.5% of adjusted gross income, the excess is deductible if you itemize — and the list of what counts (mileage to appointments, long-term care insurance premiums, therapy, dental, vision) is broader than most people assume.
- Prior-year carryovers. Capital losses above the $3,000 annual limit, charitable contributions above the AGI percentage limits, and some credits can carry forward from prior years — easy to lose track of if you switch preparers or software, since a new preparer won’t automatically know what you’re carrying forward unless you tell them or hand over last year’s return.
How to Find the Ones That Apply to You
Not every deduction on this list applies to every filer, and eligibility rules and dollar limits change year to year — several of the figures above are new for 2026 alone. Use our free calculators and AI Deduction Finder to check which of these actually apply to your specific situation before you file, rather than guessing from a list.
For educational purposes only. Not tax advice. Figures reflect 2026 IRS limits and the 2025 One Big Beautiful Bill Act’s changes to the educator expense deduction. Consult a licensed CPA for guidance specific to your situation.