Every tax season, taxpayers leave money on the table simply because they overlook deductions they are legally entitled to claim. Some of these deductions are missed due to misconceptions, others because they require consistent recordkeeping, and many because the rules change from year to year. Understanding which deductions apply to you,whether you file as an individual or operate a business, can meaningfully reduce your tax liability.

Commonly Missed Deductions for Individuals

Mortgage Interest

Mortgage interest is deductible only if you itemize on Schedule A. The IRS allows deductions on acquisition debt up to $750,000 (or $375,000 if married filing separately) for mortgages taken out after December 15, 2017. Mortgages originating before that date may qualify for the previous $1,000,000 limit. Interest on home equity loans is deductible only when the loan proceeds are used to buy, build, or substantially improve the home securing the loan. Taxpayers often miss this deduction when they refinance, change lenders, or fail to include interest reported on multiple Form 1098s.

Charitable Contributions

IRS rules allow deductions for cash donations, non‑cash contributions, and mileage driven for charitable service. Non‑cash donations must be in good used condition or better, and contributions over $250 require a written acknowledgment. Mileage for charitable service is deductible at the IRS‑approved rate of 14 cents per mile, but only if tracked contemporaneously. Taxpayers frequently miss smaller donations or fail to maintain proper documentation, which the IRS requires for all charitable deductions.

Medical Expenses

Medical expenses are deductible only to the extent they exceed a percentage of adjusted gross income. IRS Publication 502 lists eligible expenses, including dental work, orthodontics, prescription medications, medical travel, certain long‑term care costs, and medically necessary home modifications. Taxpayers often underestimate their total expenses or forget to include insurance premiums paid with after‑tax dollars.

Student Loan Interest

Up to $2,500 of student loan interest may be deductible as an adjustment to income, even if you do not itemize. Taxpayers frequently miss this deduction when servicers issue late Form 1098‑E statements or when loans are in deferment. IRS guidance also notes that interest may be deductible when a parent pays a child’s loan, provided the parent is legally responsible for the debt.

Health Savings Account (HSA) Contributions

HSA contributions reduce taxable income regardless of itemizing. IRS rules allow contributions up to annual limits for taxpayers enrolled in high‑deductible health plans. Contributions made directly to the HSA (not through payroll) must be reported manually, which is why many taxpayers miss them. HSAs offer triple tax benefits: deductible contributions, tax‑free growth, and tax‑free withdrawals for qualified medical expenses.

Educator Expenses

Eligible educators may deduct certain out-of-pocket classroom expenses. Qualifying expenses include books, supplies, software, professional development courses, and certain protective items. Many educators underestimate which expenses qualify or fail to track their purchases throughout the year. To claim the deduction with confidence, be sure to retain all receipts and supporting documentation.

The deduction is limited to $300 per eligible educator. For taxpayers who are married filing jointly, the maximum deduction is $600 if both spouses are eligible educators, but only if each spouse incurred at least $300 of qualifying expenses.

Commonly Missed Deductions for Business Owners

Home Office Deduction

The IRS allows the home office deduction when a space is used regularly and exclusively for business. Taxpayers may use the simplified method (a per‑square‑foot calculation) or actual expenses (a percentage of home expenses such as utilities, insurance, and repairs). Many business owners avoid this deduction due to outdated audit fears, despite clear IRS rules supporting it.

Vehicle Mileage and Transportation

The IRS standard mileage rate for 2026 is 72.5 cents per mile in January-June and 76 cents July-December. Business owners may deduct mileage, parking fees, and tolls. They may also choose to deduct actual vehicle expenses if that method yields a larger deduction. Mileage is commonly missed because it requires consistent tracking throughout the year.

Startup Costs

IRS rules allow businesses to deduct up to a set amount of startup and organizational costs in the first year, with the remainder amortized. These include market research, legal fees, training, and initial advertising. New business owners often fail to track these early expenses because they occur before revenue begins.

Section 179 and Immediate Asset Write‑Offs

Section 179 allows immediate expensing of qualifying equipment and certain property. Annual limits change, and misunderstanding eligibility leads to missed opportunities. Many small businesses mistakenly depreciate assets over several years instead of using Section 179 when eligible.

Business Meals

IRS rules allow a 50 percent deduction for business meals when they are ordinary, necessary, and directly related to business. Documentation must include the date, amount, and business purpose. Business owners often under‑deduct because they assume meals are not deductible or over‑deduct by including personal meals.

Health Insurance Premiums for Self‑Employed Individuals

Self‑employed taxpayers may deduct health insurance premiums for themselves and their families if they meet IRS eligibility rules. This deduction is often missed when taxpayers incorrectly assume marketplace or COBRA premiums do not qualify or when they overlook eligibility changes tied to business income.

Retirement Plan Contributions

SEP IRAs, Solo 401(k)s, and SIMPLE IRAs offer substantial deductions. IRS guidance allows contributions up to the tax filing deadline, including extensions. Business owners frequently miss these deductions because they do not revisit retirement planning during tax season.

Recordkeeping‑Dependent Deductions

IRS guidance emphasizes that deductions require documentation. Supplies, software, subscriptions, professional fees, continuing education, and small equipment purchases are often missed because receipts are not retained or categorized. Consistent bookkeeping ensures these deductions are captured.

Optimizing your 2026 tax deductions starts with a solid plan

Whether you are an individual taxpayer or a business owner, the tax code offers more opportunities for legitimate deductions than most people realize. The key is understanding what qualifies, maintaining clear records, and reviewing your financial activity with a tax professional who can help you identify missed opportunities.

WarrenJackson CPAs is committed to helping taxpayers maximize their deductions and file with confidence. If you would like a personalized review of your tax situation or guidance on planning for the year ahead, contact us for an appointment.