Business Deductions: Everything You Should Know About Tax Write-Offs

Running a business comes with a long list of expenses, and many of them can reduce your taxable income through business tax deductions. Understanding which expenses qualify, how to document them, and the limits that apply can save you thousands of dollars each year. Whether you operate as a sole proprietor, LLC, or S-corp, this guide covers the most valuable business deductions available for the 2026 tax year.

What Are Business Tax Deductions?

Business tax deductions are expenses the IRS allows you to subtract from your gross business income, reducing the amount of income subject to tax. Unlike personal deductions, business deductions are generally not subject to a floor percentage of adjusted gross income, meaning most legitimate business expenses are fully deductible. According to the IRS guidance on deducting business expenses, an expense must be both ordinary (common and accepted in your trade) and necessary (helpful and appropriate for your business) to qualify.

Business deductions directly lower your self-employment tax liability as well as your income tax, making them doubly valuable. For example, if you are in the 22% tax bracket and you claim a $1,000 deduction, you save $220 in income tax plus roughly $153 in self-employment tax — a combined savings of $373 on that single expense.

One common mistake is confusing personal and business expenses. The IRS scrutinizes deductions that appear personal in nature, so having clear separation between business and personal accounts is essential. Opening a dedicated business bank account and credit card makes tracking deductible expenses significantly easier and more defensible in an audit.

Ordinary and Necessary Business Expenses

The "ordinary and necessary" standard is the foundation of all business deductions. An ordinary expense is one that is common and accepted in your industry. A necessary expense is one that is helpful and appropriate for your business — it does not have to be indispensable. As the IRS notes, this standard gives business owners broad latitude while still requiring a genuine business purpose.

Common ordinary and necessary expenses include office supplies, advertising and marketing costs, professional fees (accountants, attorneys, consultants), business insurance premiums, rent for office or retail space, utilities, software subscriptions, and employee wages. A detailed breakdown of these categories is available from the NerdWallet guide to small business tax deductions, which lists over 20 categories of deductible business expenses.

Common Business Deduction Categories at a Glance

Category	Maximum Deduction (2026)	Key Rule
Home Office	$1,500 (simplified) or actual expenses	Must be regular and exclusive use
Vehicle Mileage	70 cents/mile (standard rate)	Business miles only; log required
Section 179 Equipment	$1,220,000	Phases out above $3,050,000
Health Insurance Premiums	100% of premiums	Net profit required; cannot be on spouse's plan
Retirement Plan (SEP IRA)	25% of compensation (up to $70,000)	Must cover eligible employees
Meals (50% rule)	50% of qualified meals	Business purpose must be documented

Home Office Deduction Rules

The home office deduction allows you to deduct expenses related to the portion of your home used exclusively and regularly for your business. The IRS offers two methods: the simplified option ($5 per square foot, up to 300 square feet, for a maximum deduction of $1,500) and the regular method (allocating actual home expenses like mortgage interest, rent, utilities, and depreciation based on the percentage of your home used for business).

To qualify, the space must be your principal place of business — meaning you use it substantially and regularly for administrative or management activities. The exclusive-use requirement means the area cannot double as a guest bedroom or personal office. However, the IRS does allow the deduction for storage of inventory or a daycare facility under separate rules. A study from the Harvard Business School found that remote work has increased home office deduction claims by more than 40% since 2020.

Self-employed individuals claim the home office deduction on Form 8829 attached to Schedule C. Employees working remotely generally cannot claim this deduction after the Tax Cuts and Jobs Act suspended unreimbursed employee expenses through 2025, though the One, Big, Beautiful Bill did not restore this provision for 2026.

Vehicle and Transportation Deductions

If you use a vehicle for business purposes, you can deduct the associated costs using either the standard mileage rate or the actual expense method. For 2026, the standard mileage rate is 70 cents per business mile, which includes depreciation, maintenance, insurance, and fuel. The IRS standard mileage rates page updates this figure annually based on transportation cost studies.

The actual expense method allows you to deduct the business percentage of all vehicle costs: gas, oil changes, repairs, tires, insurance, registration fees, lease payments, and depreciation. To use this method, you divide your business miles by total miles driven to determine the deductible percentage. If you drive 12,000 miles total and 8,000 are business-related, you deduct 66.7% of your actual vehicle expenses.

Commuting mileage — driving from home to your regular workplace — is generally not deductible. However, if you have a qualifying home office, the first trip of the day from your home office to a client location is considered business mileage. A mileage log recording the date, destination, purpose, and number of miles for each business trip is essential for substantiating your deduction.

Meals and Entertainment Expenses

The rules for meals and entertainment deductions have changed significantly in recent years. Under current law, business meals are generally 50% deductible if you are present, the meal is not lavish, and you discuss business with a client, customer, or employee before, during, or after the meal. Entertainment expenses — such as tickets to sporting events, concerts, or golf outings — are no longer deductible as they were before the Tax Cuts and Jobs Act.

Temporary 100% deduction rules for business meals from restaurants expired after 2022, so 2026 follows the standard 50% limit. Meals provided to employees for the convenience of the employer (such as meals in a company cafeteria) are 100% deductible. Food and beverage costs for office parties and holiday events are also 100% deductible as de minimis fringe benefits.

Proper documentation for a meal deduction should include the amount, date, location, business purpose, the business relationship of the persons entertained, and a receipt for amounts over $75. The DOI estimates that inadequate documentation is the leading cause of meal deduction disallowances during IRS audits.

Health Insurance and Self-Employment Deductions

Self-employed individuals can deduct 100% of their health insurance premiums for themselves, their spouse, and their dependents. This deduction is taken on Schedule 1 of Form 1040 and reduces adjusted gross income — meaning it is available even if you do not itemize. To qualify, you must have net profit from your business and cannot be eligible for employer-sponsored health insurance through your spouse's employer.

The self-employment tax deduction is another valuable write-off. When you calculate self-employment tax on Schedule SE, you deduct the employer-equivalent portion (7.65%) of your self-employment tax from your adjusted gross income. While this does not reduce your self-employment tax liability itself, it lowers your income tax. The IRS Self-Employed Individuals Tax Center provides worksheets and calculators to help determine these deductions accurately.

If your business is structured as an S-corp, health insurance premiums paid on behalf of a shareholder-employee who owns more than 2% of the company are deductible by the corporation and included in the employee's gross income, then deducted on the employee's personal return. This approach can yield payroll tax savings while still providing the individual deduction.

Retirement Plan Deductions for Business Owners

Retirement contributions are one of the most powerful business deductions because they reduce current taxable income while building long-term savings. The SEP IRA allows you to contribute up to 25% of your net self-employment income, with a maximum contribution of $70,000 for 2026. SEP IRAs are easy to set up and require minimal paperwork, making them popular among sole proprietors and freelancers.

The Solo 401(k) offers even higher contribution limits for business owners with no employees. For 2026, you can contribute up to $23,500 as an employee elective deferral plus up to 25% of net earnings as an employer contribution, for a total of up to $70,000 (or $77,500 if age 50 or older with catch-up contributions). A SIMPLE IRA allows contributions of up to $16,600 in 2026, with a $3,500 catch-up for those 50 and older.

Each plan type has different setup deadlines, contribution deadlines, and employee coverage requirements. The SEP IRA deadline generally aligns with your tax filing deadline (including extensions), while Solo 401(k) contributions must be elected by December 31 but can be funded by the tax deadline. Consulting a tax professional is recommended when choosing the right retirement plan for your business structure.

Business Equipment and Section 179

Section 179 of the Internal Revenue Code allows businesses to deduct the full purchase price of qualifying equipment and software purchased or financed during the tax year. For 2026, the Section 179 deduction limit is $1,220,000, with a phase-out threshold of $3,050,000. This means businesses that spend up to $3,050,000 on equipment can deduct the full amount, with the deduction reducing dollar-for-dollar above that threshold.

Qualifying property includes machinery, computers, office furniture, vehicles used for business (subject to limits), software, and certain improvements to commercial buildings. The equipment must be placed in service — meaning ready and available for use — by December 31 of the tax year. Bonus depreciation allows an additional 80% first-year deduction for qualified property placed in service in 2026, down from 100% in 2022 and 2023.

A cost-benefit analysis from the Harvard Kennedy School small business tax research program found that Section 179 incentives significantly increased small business investment in productivity-enhancing equipment. Leased equipment is generally not eligible for Section 179, but lease payments themselves are fully deductible as ordinary business expenses.

Recordkeeping and Documentation Requirements

The IRS requires you to maintain records that substantiate every deduction you claim. While there is no single required format, your records must clearly show the amount, date, business purpose, and business relationship for each expense. For vehicle expenses, a mileage log recording each trip's date, mileage, destination, and business purpose is strongly recommended. Digital tools such as MileIQ, QuickBooks Self-Employed, and Expensify can automate much of this tracking.

Receipts should be kept for any expense over $75, and for lodging expenses regardless of amount. Bank and credit card statements alone are generally not sufficient to prove business purpose — the IRS wants to see documentation that explains why an expense was incurred. The IRS recommends retaining records for at least three years from the date you file your return, though records for assets should be kept until the depreciation period ends plus three years.

According to NerdWallet's guide to tax deduction documentation, organizing receipts by category throughout the year rather than scrambling at tax time results in more complete deductions and less stress. Cloud-based receipt scanners and expense management software make year-round recordkeeping practical for even the smallest businesses.

Frequently Asked Questions

What is the difference between a deduction and a credit? A deduction reduces your taxable income, while a credit reduces your tax liability dollar-for-dollar. For example, a $1,000 deduction saves you $220 if you are in the 22% bracket, while a $1,000 credit saves you the full $1,000.

Can I deduct business losses? Yes. If your business expenses exceed your business income, the net loss can offset other income on your tax return, subject to hobby loss rules and at-risk limitations. The IRS may scrutinize businesses that report losses for multiple consecutive years.

Are startup costs deductible? You can deduct up to $5,000 in startup costs in your first year of business, with the remainder amortized over 15 years. Startup costs include market research, advertising, training, and legal fees incurred before your business begins active operations.

Do I need to be profitable to claim deductions? Generally, yes — you need business income to offset with deductions. However, you can carry forward excess deductions in the form of net operating losses to offset future income, subject to limitations under the Tax Cuts and Jobs Act and subsequent legislation.

What happens if the IRS disallows a deduction? You will owe additional tax plus interest and possibly penalties. If the disallowance is due to inadequate documentation, you may be able to provide additional records during the appeals process. Working with a qualified tax professional can help prevent common deduction mistakes.

This article is for informational purposes only and does not constitute professional tax or legal advice. Always consult a qualified tax professional for guidance specific to your business situation.