The golden rule of business deductions
Every business expense you deduct must pass one test: was it ordinary and necessary for your business?
- Ordinary — common and accepted in your industry. A photographer buying a camera is ordinary. A photographer buying a yacht is not.
- Necessary — helpful and appropriate for your business. Not required or essential — just relevant and reasonable.
If you can answer "yes" to both, it's likely deductible. When in doubt, keep the receipt and let your CPA decide.
The biggest deduction mistake isn't claiming something you shouldn't — it's missing things you could claim because you didn't keep records. Track every business expense. Keep every receipt. You can always decide later whether something qualifies. You can't reconstruct records you never kept.
Why deductions matter more than you think
For self-employed people and LLC owners, deductions reduce your net profit on Schedule C. That net profit is subject to both income tax and self-employment tax (15.3%). So every $1,000 you deduct saves you approximately:
Because deductions reduce both income tax and self-employment tax simultaneously, their value is higher for self-employed people than for W-2 employees who can only take the standard deduction.
The major deduction categories
Click any category to expand the details:
What you cannot deduct
Just as important as knowing what you can deduct is knowing what you can't:
| Not deductible | Why |
|---|---|
| Personal expenses of any kind | Must be ordinary and necessary for the business — personal use doesn't qualify |
| Commuting from home to your regular office | Commuting is personal travel, not business travel |
| Fines and penalties | IRS penalties, parking tickets, and legal fines are not deductible |
| Clothing (unless a required uniform) | Clothing you can wear outside of work is personal, even if you bought it for business meetings |
| Meals while working alone | Solo meals while working — unless traveling away from home overnight for business |
| Entertainment expenses | Post-2017, entertainment (concerts, sporting events, golf) is no longer deductible |
| Personal portion of mixed-use expenses | Only the business percentage of a partly-personal expense is deductible |
| Capital improvements (in most cases) | Must be depreciated over time, not deducted all at once — though Section 179 may allow full first-year deduction |
The record-keeping minimum
You don't need an elaborate system. The minimum required for each expense:
- Receipt — amount, date, vendor. A photo on your phone is acceptable.
- Business purpose — a brief note explaining why this was a business expense. For meals: who was there and what was discussed.
- Vehicle mileage — a log with date, starting point, destination, and business purpose for every business trip.
Use a dedicated business bank account and business credit card for all business expenses. This automatically creates a transaction record for every purchase. At year end, export your statements and categorize transactions — it takes a fraction of the time compared to sorting through personal accounts. Add a brief note to your phone's notes app after any meal or unusual expense while it's fresh in your memory.