Business Tax Deductions: The Complete List for Small Business Owners (2026)

The Rule: Ordinary and Necessary

Under Section 162 of the Internal Revenue Code, a business expense is deductible if it is both "ordinary" (common and accepted in your trade or business) and "necessary" (helpful and appropriate for your business). If an expense meets that test and you have documentation, it's likely deductible.

The IRS doesn't publish an exhaustive list of deductible expenses — the test is principle-based. That's why so many legitimate deductions go unclaimed: business owners don't know to look for them, and not every tax preparer proactively asks.

Office and Workspace Deductions

Home Office Deduction

If you use part of your home regularly and exclusively for business, you can deduct a portion of your home expenses. There are two methods:

• Simplified method: $5 per square foot of office space, up to 300 square feet ($1,500 max)
• Actual expense method: Percentage of home used for business × actual home expenses (mortgage interest/rent, utilities, insurance, repairs, depreciation)

The actual expense method is almost always larger. A 200 sq ft office in a 2,000 sq ft home = 10% of all home expenses. On $30,000 in annual home costs, that's $3,000 in deductions.

Rented Office Space

100% of rent for a commercial office, co-working membership, storage unit used for business, or meeting room fees is deductible.

Vehicle and Transportation Deductions

Standard Mileage Rate

For 2025, the IRS standard mileage rate is 70 cents per mile for business use. If you drive 15,000 business miles in a year, that's a $10,500 deduction.

Actual Vehicle Expense Method

Instead of the standard rate, you can deduct the actual costs of operating your vehicle in proportion to business use: gas, insurance, maintenance, repairs, registration, and depreciation. This method requires more recordkeeping but can yield a larger deduction for expensive vehicles.

Section 179 and Bonus Depreciation for Vehicles

Certain business vehicles (SUVs, trucks, vans used more than 50% for business) qualify for accelerated depreciation under Section 179 or bonus depreciation. Passenger vehicles have annual depreciation caps, but larger vehicles (over 6,000 lb GVWR) can qualify for first-year expensing of the full purchase price.

Payroll and Compensation Deductions

• Employee salaries and wages: 100% deductible
• Employer payroll taxes (FICA): 100% deductible
• Contract labor / 1099 payments: 100% deductible (requires issuing 1099-NEC for payments over $600)
• Employee benefits: Health insurance premiums, dental/vision, life insurance up to $50,000
• Retirement plan contributions: Employer contributions to 401k, SEP-IRA, SIMPLE IRA — 100% deductible

Health Insurance Deductions

Self-employed individuals can deduct 100% of health, dental, and long-term care insurance premiums paid for themselves, their spouse, and dependents — directly from gross income (not subject to the 7.5% AGI floor for medical expenses). This is one of the most valuable deductions available and is frequently missed.

For S-Corp owners: the company pays the health insurance premiums and includes them in your W-2 wages, and you then deduct them on your personal return as self-employed health insurance.

Retirement Contributions

Pre-tax retirement contributions are among the most powerful tax deductions available. For 2025:

• Solo 401(k): Up to $70,000 ($77,500 if age 50+) — employee + employer contributions combined
• SEP-IRA: Up to 25% of net self-employment income or $70,000, whichever is less
• SIMPLE IRA: Up to $16,500 employee contribution + employer match
• Defined Benefit Plan: Potentially $275,000+ annually for high earners

Marketing and Advertising

• Website development, hosting, and maintenance
• SEO services and digital advertising (Google Ads, Meta Ads)
• Business cards, brochures, print advertising
• Sponsorships and branded merchandise
• Photography and videography for business use

Professional Services

• Accounting and bookkeeping fees
• Legal fees for business matters
• Business consulting fees
• Financial advisory fees for business investments

Technology and Software

• Computers, tablets, smartphones (business-use percentage)
• Software subscriptions (accounting, project management, design tools)
• Cloud storage and business apps
• Phone and internet (business-use percentage)

Education and Professional Development

Education expenses are deductible if they maintain or improve skills required in your current business (not required to meet minimum requirements for a new career or qualify you for a new profession).

• Industry conferences and trade shows
• Professional certifications and continuing education
• Business books, subscriptions to industry publications
• Online courses and training programs

Business Meals

Business meals are 50% deductible when there is a genuine business purpose: client meetings, team meetings, meals during business travel. You must document the business purpose, who attended, and the business relationship.

Note: Company parties and events for the benefit of all employees (holiday parties, team outings) are 100% deductible.

The Bottom Line on Deductions

Most small business owners are missing $3,000–$15,000 in annual deductions — not because the expenses aren't there, but because they're not being captured and documented properly. The combination of a complete tax structure review and a systematic deduction audit typically produces the highest total tax savings.

A free consultation can identify which deductions you're missing and help you build the documentation system to capture them going forward.