The home office deduction is one of the most commonly skipped, not because business owners do not have a qualifying space, but because they are not sure it will hold up. If you have a dedicated space used regularly and exclusively for business, it qualifies, and the deduction covers a proportional share of rent, utilities, and home insurance.
Vehicle expenses are similarly underutilized. If you use your personal vehicle for business purposes, you can deduct either the actual expenses proportional to business use, or the standard mileage rate. The catch: you need a mileage log, and most owners do not keep one consistently enough to support the deduction at filing time.
What a Real Mileage Log Is Actually Worth
Consider a home-services contractor who drives to client sites constantly but has never kept a mileage log, assuming it's not worth the hassle for what seems like a modest deduction. Starting a simple phone-based mileage tracking app at the start of a new tax year, they log 14,200 business miles by December 31, all tied to specific client jobs with dates and addresses recorded automatically.
At the standard mileage rate, this comes to a deduction of several thousand dollars, directly reducing both income tax and self-employment tax on that amount. In the prior year, without any log at all, this same contractor claimed a rough estimate of "about 8,000 miles" on their return, a number their tax preparer had to caveat as unsupportable if ever questioned, since an estimate without contemporaneous records does not hold up under IRS scrutiny. The habit of logging trips as they happen, rather than reconstructing them later from memory, is what turns this into a real, defensible deduction instead of a guess.
Retirement contributions through a SEP-IRA, Solo 401(k), or SIMPLE IRA are among the most powerful deductions available to self-employed individuals. These contributions reduce taxable income dollar for dollar while building retirement savings simultaneously, making them one of the few deductions that also builds long-term wealth.
Health insurance premiums paid for yourself and your family are fully deductible if you are self-employed and not eligible for employer-sponsored coverage through a spouse. This one deduction alone can reduce taxable income by several thousand dollars for most owners.
Business education, professional subscriptions, software, and accounting fees (including what you pay a bookkeeper or tax preparer) are all fully deductible. The key in every case is clean bookkeeping that correctly categorizes these expenses throughout the year, deductions you cannot document are deductions you cannot claim.
The Two Home Office Calculation Methods, Compared
The simplified home office method allows a flat $5 per square foot of qualifying space, up to 300 square feet, a maximum $1,500 deduction, calculated with no need to track actual home expenses. The regular method instead calculates the business-use percentage of your home and applies it to actual expenses, mortgage interest or rent, utilities, insurance, and depreciation, which for a larger dedicated space in an expensive area can produce a meaningfully larger deduction than the simplified flat-rate method, at the cost of more detailed recordkeeping.
Which method actually produces the larger deduction depends entirely on your specific home costs and office size, calculating both and picking whichever is larger is worth doing rather than defaulting to the simpler option out of convenience.
It's worth building a simple habit of asking, for every business purchase, whether it was genuinely ordinary and necessary for the business, the actual legal standard the IRS applies to deductions. A purchase that clearly meets that standard is worth tracking and claiming, even if it feels minor; the small, consistently claimed deductions often add up to more over a full year than the occasional large one.