7 deductions self-employed people most often miss
Gary FongShare
Part 2 of a 5-part series on how AI changed the IRS audit landscape — and what self-employed Schedule C filers should do about it. Read Part 1 if you haven't.
You're probably overpaying.
Not because you're doing anything wrong. Because the tax software you used in March didn't ask you the right questions. It computed your taxes. It didn't audit them.
If you file a Schedule C — photographer, designer, consultant, contractor, therapist, coach, real estate agent, Etsy seller, tutor, writer, anyone self-employed — there's a meaningful chance you're leaving money on the table.
The IRS isn't going to call you up and say "hey, you forgot to claim this." Tax software doesn't volunteer it either. The deductions exist, they're legal, they're documented in the Internal Revenue Code, and most self-employed people fail to take them.
These are the seven we see missed most often. Each one is potentially worth four figures in tax savings. Several of them, taken together, can swing a return from "owed" to "refund."
1Self-Employed Health Insurance (SEHI)
If you paid health insurance premiums for yourself, your spouse, or your dependents — and you weren't eligible for an employer-subsidized plan — you can deduct 100% of those premiums above the line. That means it reduces your AGI before any other calculations.
Why people miss it: tax software often only triggers the SEHI prompt if you've explicitly indicated you're self-employed with no employer health coverage. If you also had a brief W-2 job during the year, the software may skip the prompt entirely. The deduction is still yours for the months you were self-employed with no eligible employer plan.
What to claim: medical, dental, vision, AND long-term care premiums. Many people remember the medical and forget the dental — that's $500-1,500 of extra deduction sitting unclaimed.
2Home office deduction
The deduction most people are afraid of. Conventional wisdom says it's an audit trigger. The reality is more nuanced: an exaggerated home office is an audit trigger. A properly calculated, well-documented home office is one of the safest deductions on Schedule C.
Two methods exist. The simplified method caps you at $5 per square foot up to 300 sq ft — max $1,500. The actual expense method uses your home office square footage as a percentage of total home square footage, applied to rent/mortgage interest, utilities, insurance, depreciation.
For most people, actual expense generates a 2-3x larger deduction.
What to claim: if you have a room (or part of a room) used regularly AND exclusively for your business, you qualify. Measure to the inch. Document with a floor plan and dated photo. Compute the percentage to two decimal places — not a round 25%, an actual percentage like 23.47%.
What to avoid: claiming a room you also use personally. "Exclusive use" is the rule the IRS enforces hardest. A home office that's also the guest bedroom is not a home office.
3The deductible half of self-employment tax
When you pay self-employment tax (15.3% of net Schedule C income for Social Security and Medicare), you also get to deduct half of that tax as an adjustment to income.
Most software handles this automatically. But not always — particularly in years where you also have W-2 income that pushes your wage base above the Social Security limit. In those years, the calculation gets complex and software occasionally drops the deduction entirely.
What to check after filing: look at Schedule 1 Line 15. Compare to half of Schedule SE Line 12. If Line 15 is meaningfully smaller than half of Line 12 — call your CPA. Something's wrong.
4Section 179 expense (or bonus depreciation)
If you bought equipment for your business — a camera, computer, vehicle over 6,000 lbs, machinery, office furniture — you can typically deduct the entire purchase price in year one rather than depreciating it over five or seven years.
Section 179 lets you expense up to $1.16 million of equipment in the year you placed it in service. Bonus depreciation lets you write off 60% of the cost in 2024 (phasing down annually).
Why people miss it: they bought the equipment, took the standard 5-year depreciation, and never realized year-one expensing was available. Buying a $4,800 camera and depreciating 20%/year = $960 deduction. Electing Section 179 = $4,800. The difference at a 30% marginal rate: $1,152 in tax savings, in your pocket this year.
→ Tip: If you missed this in a prior year, you can amend. Form 1040-X within three years of filing the original return.
5Retirement contributions (SEP-IRA or Solo 401(k))
Not a Schedule C deduction — an adjustment to income on Schedule 1 — but it lives in the same conversation because it's the single biggest legal tax shelter available to self-employed people.
SEP-IRA: contribute up to 20% of net Schedule C income (after the half-SE-tax deduction), capped at $69,000 for 2024.
Solo 401(k): same employer portion PLUS an employee deferral of $23,000 ($30,500 if 50+), capped at the same $69,000 total but achievable with much less income.
Why people miss it: they never set the account up. SEP-IRAs and Solo 401(k)s are free to open at Fidelity, Schwab, or Vanguard. And you can contribute up to the tax filing deadline of the following year. Most people don't realize they can fund a 2024 SEP-IRA in March of 2025.
→ The math: At a 30% marginal rate, contributing $20,000 to a SEP saves $6,000 in current-year tax — money that goes into your retirement account instead of the IRS.
6Qualified Business Income (QBI) deduction
The big deduction nobody talks about clearly. Self-employed people get to deduct an additional 20% of their qualified business income, on top of all other Schedule C deductions. For most filers it's automatic — but the calculation has phase-outs and limitations that tax software handles imperfectly.
The deduction is reduced for "specified service trades or businesses" (SSTBs) — accounting, law, medicine, consulting, financial services, performing arts — once your taxable income exceeds $191,950 (single) or $383,900 (married filing jointly) in 2024. Below those thresholds, even SSTBs get the full 20%.
What to check: look at Line 13 of Form 1040 (your QBI deduction). Compare to 20% of (Schedule C Line 31 net profit − half of SE tax − your SEP-IRA contribution). If Line 13 is meaningfully smaller and your income is below the threshold — something's off and you may be leaving money behind.
7Vehicle business use — properly tracked
Most self-employed people default to standard mileage because it's simpler. For high-mileage filers (15,000+ business miles/year), that's usually the right call. For lower-mileage filers with an expensive vehicle, actual expenses can generate a 2-3x larger deduction.
Where people leave money: they don't track miles consistently. They use an estimate at year-end ("about 12,000 miles") instead of a contemporaneous mileage log. The IRS requires a contemporaneous log under Treas. Reg. §1.274-5T — and without one, every mile claimed is subject to disallowance on audit.
The fix: MileIQ, Stride, QuickBooks Self-Employed, or just a Google Sheet updated weekly. Free options exist. The mileage is yours; the documentation discipline is what keeps it.
The point isn't to be aggressive.
It's to be complete.
None of these are loopholes. None of them require creative interpretation of the tax code. They're documented in the IRC, IRS Publication 535 (Business Expenses), and Publication 463 (Travel, Gift, and Car Expenses). The reason they get missed isn't because they're hidden — it's because tax software doesn't ask the right questions and most self-employed people don't know to ask.
AuditClaude's Three-Pass System runs through all seven of these — plus dozens more category-by-category — on your specific return:
- Pass One finds what's been missed.
- Pass Two stress-tests what you've already claimed for risk.
- Pass Three cross-verifies every finding across Claude, ChatGPT, and Gemini before you bring it to your CPA.
The first pass alone, in our case study, found $15,261 in missed deductions on a single photographer's return. Even at a moderate marginal rate, that's $4,500+ in tax dollars that went back into her pocket.
Keep your CPA.
This needs saying again: AuditClaude does not replace your CPA. A CPA or EA filing on your behalf provides reasonable-cause defense under Treas. Reg. §1.6664-4 if the IRS does come asking. AI doesn't provide that.
What AuditClaude does is hand your CPA a clean, pre-audited file so the deductions actually make it onto your return — and the risks don't.
AuditClaude — The Three-Pass System for self-employed Schedule C filers.
A complete methodology playbook, a Maya Parker case study showing the system in action, and twelve copy-paste prompts that take you from "what did I miss" to "here's the audit defense file." Digital download.