Every dollar of legitimate deduction you miss is profit handed to the IRS voluntarily. Yet most small business owners miss several — not because the rules are secret, but because nobody keeps records well enough to claim them. Here's the practical checklist, in plain English, with the record-keeping habit that makes each one stick.
The everyday deductions (that still get missed)
- Software & subscriptions — accounting tools, design apps, cloud storage, industry databases. Small monthly amounts that add up to thousands.
- Professional services — bookkeeping, accounting, legal and consulting fees are fully deductible. Yes, hiring a bookkeeper is itself a deduction.
- Business insurance — liability, professional indemnity, business property, cyber.
- Bank & payment fees — account fees, wire charges, and every Stripe/PayPal/Square processing fee. E-commerce sellers routinely miss thousands here because processors deposit net amounts.
- Education — courses, books, conferences and training that maintain or improve skills for your existing business.
- Marketing & advertising — ads, website costs, email tools, sponsorships.
Home office: simpler than its reputation
If part of your home is used regularly and exclusively for business, you likely qualify. Two ways to claim it:
| Method | How it works | Best for |
|---|---|---|
| Simplified | $5 per square foot, up to 300 sq ft (max $1,500) | Small spaces, minimal record-keeping |
| Actual expense | Business-use % of rent/mortgage interest, utilities, insurance, repairs | Larger dedicated spaces, higher housing costs |
The "exclusively" part matters — a dedicated room or clearly defined area, not the kitchen table. Measure it once, photograph it, and the deduction defends itself.
Vehicle expenses
Business driving (client visits, supply runs, bank trips — not commuting) is deductible via either the standard mileage rate (a per-mile rate the IRS sets annually) or actual expenses (business-use share of fuel, insurance, repairs, depreciation). The catch: both methods require a mileage log. A simple app that auto-tracks trips turns this from an audit risk into free money.
The big-ticket items
Equipment & Section 179
Computers, machinery, furniture and similar business assets can often be deducted in full in the year of purchase rather than depreciated over years, using Section 179 expensing and bonus depreciation. The limits are generous for small businesses and change annually — this is a "confirm the current-year number" item, but the takeaway is simple: big purchases usually don't have to wait years to pay off at tax time.
Retirement contributions
A Solo 401(k) or SEP-IRA lets self-employed owners deduct substantial contributions — often tens of thousands of dollars — while building their own wealth instead of the IRS's. If you're profitable and have no retirement plan, this is typically the single biggest deduction you're missing.
Self-employed health insurance
Self-employed owners can generally deduct health, dental and long-term-care premiums for themselves and family — an above-the-line deduction that many miss entirely.
Startup costs
Up to $5,000 of qualifying startup expenses (and $5,000 of organisational costs) can typically be deducted in year one, with the rest amortised. Launched recently? Don't leave this behind.
Deductions with special rules
- Business meals — generally 50% deductible when there's a genuine business purpose. Note who you met and why on the receipt.
- Travel — flights, lodging and transport for business trips are deductible; the family vacation portion is not. Keep the business purpose documented.
- Contract labor — payments to freelancers are deductible; pay anyone $600+ in a year and you'll also owe them a 1099 (see our 1099 vs W-2 guide).
The uncomfortable truth: deductions aren't found in April. They're captured all year by clean bookkeeping. A shoebox of receipts in tax season recovers a fraction of what properly categorised books capture automatically. That's the real ROI of professional bookkeeping.
Frequently Asked Questions
What can a small business write off in 2026?
Ordinary and necessary business expenses: software, professional fees, insurance, marketing, payment processing fees, business meals (generally 50%), business travel, home office, vehicle use, equipment (often fully expensed via Section 179), retirement plan contributions and health insurance premiums for the self-employed, among others.
Can I claim a home office deduction if I rent?
Yes. Renters can claim either the simplified rate ($5 per square foot up to 300 sq ft) or the business-use percentage of rent and utilities under the actual-expense method. The space must be used regularly and exclusively for business.
What is the biggest tax deduction small business owners miss?
For profitable owners, usually retirement contributions (Solo 401(k) or SEP-IRA), which can shelter tens of thousands of dollars. The most commonly missed everyday item is payment-processor fees, because Stripe and PayPal deposit net amounts and the fees never appear as a visible expense.
This article is general information, not personalised tax, legal or accounting advice. Rules and thresholds change — confirm current-year figures with the IRS or a qualified professional before acting. Ask Accounts Buddy if you'd like help applying any of this to your business.