Most small business owners know to deduct rent, payroll, and materials. The deductions that get missed tend to be the ones that require consistent tracking throughout the year or the ones people simply don’t realize they qualify for.

Vehicle mileage is probably the single most underreported deduction. Contractors, real estate agents, consultants, and service businesses drive constantly for work but don’t log the trips. The IRS standard mileage rate for 2024 is 67 cents per mile. If you drive 15,000 business miles a year and don’t track them, you’re giving up roughly $10,000 in deductions. Use a mileage tracking app and log every business trip. Driving to a job site, meeting a client, picking up supplies, going to the bank for the business. It all counts.

The home office deduction gets skipped because people have heard it triggers audits. That’s outdated thinking. If you have a dedicated space used exclusively for business, take the deduction. The simplified method gives you $5 per square foot up to 300 square feet. That’s $1,500 you’re leaving on the table for no good reason.

Health insurance premiums are deductible for self-employed business owners, and many don’t realize it. If you’re paying for your own health, dental, or long-term care insurance and you’re not covered by a spouse’s employer plan, you can deduct the full premium. This isn’t an itemized deduction on Schedule A. It goes directly on your return as an adjustment to income, which means you benefit even if you take the standard deduction.

Retirement contributions through a SEP-IRA or Solo 401(k) reduce your taxable income significantly. A SEP-IRA lets you contribute up to 25% of net self-employment income. Many business owners don’t set these up because they feel like they can’t afford it, but even modest contributions save real money on taxes while building retirement savings.

Small equipment and tools under $2,500 per item can be expensed immediately under the de minimis safe harbor rule. Contractors, tradespeople, and service businesses buy tools and supplies throughout the year and forget to track the smaller purchases. A $200 drill here, a $150 set of parts there. Over twelve months those add up to thousands in missed deductions.

Software subscriptions are another category that slips through the cracks. QuickBooks, scheduling apps, project management tools, cloud storage, website hosting, email marketing platforms. Each one might be $15 to $100 per month, but collectively they represent a meaningful annual expense that’s fully deductible.

Cell phone and internet bills are partially deductible based on business use. If you use your personal phone 60% for business, 60% of the bill is deductible. Most small business owners either skip this entirely or don’t know they can claim it.

Professional fees for your accountant, bookkeeper, and attorney are deductible. So are licensing fees, continuing education, industry association dues, and certification renewals. Business owners pay these costs and then forget to tell their tax preparer about them because they seem minor individually.

The common thread with all of these is tracking. You qualify for the deduction but you don’t have documentation to support it at tax time. Working with a tax strategy professional before year end gives you time to capture what you’ve missed and plan for what’s ahead. By April, it’s too late to go back and reconstruct mileage logs or remember every small purchase.

The business owners we work with through our Tampa Bay bookkeeping services consistently find that once expenses are categorized properly each month, deductions stop falling through the cracks. The books become the documentation. When tax time comes, everything is already organized and nothing gets forgotten.