37 Small Business Tax Deductions Every Entrepreneur Should Know in 2025

The IRS released the 2025 thresholds in November 2024, and a lot has shifted from the prior year. The standard deduction is up, the Section 179 limit is up, and the bonus depreciation phase-down continues at 40%. If you're a sole proprietor, single-member LLC, or S-Corp owner, here's what actually saves you money this year.

1. Home Office (Form 8829)

Two methods. Pick whichever gives you a bigger deduction:

• Simplified: $5/sq ft up to 300 sq ft = $1,500 max. No depreciation recapture on sale.
• Actual: % of home used for business × (rent + utilities + insurance + repairs + depreciation). Better if you live in San Francisco, Manhattan, or another high-rent metro.

Eligibility: regular and exclusive use, principal place of business OR a separate structure used for the business.

2. Vehicle (Standard Mileage vs. Actual)

For 2025, the IRS standard mileage rate is 70¢/mile for business use (up from 67¢ in 2024). Track every business trip — apps like MileIQ or your bookkeeping software handle this automatically.

If you bought a vehicle in 2025, the actual-expense method may dominate, especially with bonus depreciation still at 40%.

3. Section 179 + Bonus Depreciation

For 2025, you can expense up to $1,250,000 of equipment, software, and qualifying improvements in year 1 under Section 179 (phase-out starts at $3,130,000). Bonus depreciation drops from 60% (2024) → 40% (2025) → 20% (2026) → 0% (2027). If you're buying $50K+ in equipment, this matters.

4. Qualified Business Income (QBI) — Section 199A

A 20% deduction on pass-through income (sole prop / LLC / S-Corp / partnership). 2025 phase-out thresholds:

• Single: $250,000
• MFJ: $500,000

Specified Service Trades or Businesses (SSTBs — law firms, consulting, health, financial services) phase out completely above the threshold. If you're at or near the threshold, S-Corp election + reasonable salary planning becomes critical.

5. Health Insurance Premiums (Self-Employed)

100% deductible above-the-line on Schedule 1 — for you, your spouse, your kids, and any dependent under 27. Doesn't reduce SE tax but it does reduce AGI.

6. Retirement: SEP-IRA, Solo 401(k), SIMPLE IRA

The biggest single tax shelter most small business owners ignore.

• Solo 401(k): up to $69,000 in 2024 ($70,000 in 2025), $76,500 if 50+ with catch-up.
• SEP-IRA: 25% of net SE income, up to $69K (2024) / $70K (2025).
• SIMPLE IRA: $16,000 employee + 3% employer match (2024 limits).

7-37: The Full List

Below is the complete list of deductible categories you should be tracking. We've grouped them by Schedule C line so you can match them to your bookkeeping:

Operations:

• Advertising and marketing (Sch C L8)
• Bank fees and credit card processing (L10)
• Contract labor / 1099 contractors (L11)
• Office supplies and small equipment (L18, L22)
• Software subscriptions (L18 / L27a) — Adobe, Notion, GitHub, Slack, etc.
• Postage and shipping
• Continuing education and certifications (L27a)

Real estate & utilities:

• Office rent (L20b) — coworking spaces qualify
• Utilities, including internet and business phone (L25)
• Repairs and maintenance (L21)
• Insurance — general liability, E&O, cyber (L15)

Professional services:

• Legal fees (L17)
• Accounting and bookkeeping (L17)
• Tax prep (L17)
• Payroll services (L17)
• Consulting (L17)

Travel & meals:

• Airfare, hotels, rental cars for business (L24a)
• Business meals — 50% deductible (L24b)
• Conference fees and travel
• Per diem rates (when applicable)

Wages & benefits:

• W-2 wages (L26)
• Employer payroll taxes
• Group health, dental, vision (L14)
• Retirement plan contributions (L19)
• Workers' comp insurance

Capital & financing:

• Business loan interest (L16b)
• Vehicle loan interest (proportional to business use)
• Bad debts written off (L27a)
• Depreciation on equipment (L13, Form 4562)

Industry-specific:

• Materials and inventory (COGS, Part III)
• Subscriptions to trade publications
• Licenses, permits, and franchise fees (L23)
• Trademark and patent fees

What Most Owners Miss

The boring ones. Bank fees. Credit card processing fees. Domain renewals. Website hosting. State franchise tax (huge in California — $800 minimum). Gusto/ADP subscription fees. The $9.99 Canva subscription. They add up to $3K-$8K of deductions per year that go unclaimed because they're not in the bookkeeping system.

That's exactly what bank-statement parsers like Accountaxed are for — every deductible transaction gets flagged automatically, with the IRS line number attached so your accountant can see the audit trail.

The "Ordinary and Necessary" Test

Every deduction has to clear two bars under IRC §162:

1. Ordinary — common and accepted in your industry
2. Necessary — helpful and appropriate for your business

A photographer deducting a $2,000 lens? Ordinary and necessary. A photographer deducting a $50,000 boat? Probably not.

Filing Strategy for 2025

Plan your purchases. If you need new equipment, buying in December vs. January determines which year you can expense it. Section 179 is "placed in service" — the asset must be used in the business by year-end.

Maximize retirement contributions. Solo 401(k) deadlines extend to your tax-filing deadline including extensions, so you have until October 15, 2026 to fully fund 2025 contributions.

Don't mix personal and business. This is the single biggest audit trigger for small businesses. Keep a dedicated business bank account from day one.

If you want to see exactly which of these deductions show up in your bank statements (and which you're missing), upload a free P&L analysis — it categorizes every transaction against this list and gives you the audit-ready summary.