What qualifies as a business expense?

A business expense is any cost that is "ordinary and necessary" for conducting business, as defined by the IRS. Ordinary means common and accepted in your industry. Necessary means helpful and appropriate (not indispensable). Common categories include travel, meals with business purpose, office supplies, professional services, equipment, and communication costs. Personal expenses never qualify regardless of when or where they're incurred.

What documentation do you need for business expenses?

The IRS requires four elements for travel and meal expenses: the amount, date, business purpose, and (for meals) the names and business relationship of attendees. Receipts are required for expenses over $75. Most companies require receipts for all expenses regardless of amount, plus expense category codes, project assignments, and manager approval.

Are business meals still tax-deductible?

Yes, but at 50%. The temporary 100% deduction for restaurant meals (2021–2022) has expired. Business meals are deductible at 50% when there is a clear business purpose and the expense is not lavish or extravagant. Documentation must include who attended and the business topic discussed. Meals provided for the convenience of the employer on business premises have separate rules.

How does Navan help manage business expenses?

Navan captures business expenses automatically through corporate card integration and mobile receipt scanning. The platform categorizes transactions, validates them against company policy rules in real time, matches receipts to card charges, and routes approvals to managers. This eliminates manual expense reports and ensures proper documentation for both tax and audit purposes.

What happens if a business expense isn't properly documented?

Under an accountable plan, undocumented reimbursements must be reclassified as taxable wages, creating payroll tax liability for both the employer and employee. For the company's tax return, undocumented expenses lose their deductibility, increasing taxable income. Internally, undocumented expenses are typically rejected by the finance team, delaying or denying reimbursement to the employee.

Can employees deduct unreimbursed business expenses?

Under current U.S. tax law (since the Tax Cuts and Jobs Act of 2017), W-2 employees cannot deduct unreimbursed business expenses on their personal tax returns. This deduction was suspended through 2025 and has been extended. Only self-employed individuals and certain categories (performing artists, fee-basis state officials, Armed Forces reservists) retain this deduction.

Navan - Business Travel Solutions & Expense Management

Business Expense

A cost incurred in the ordinary and necessary operation of a business that is potentially tax-deductible, including travel, meals, supplies, equipment, and professional services, subject to documentation requirements established by the IRS and the company's own expense policy.

Victoria Landsmann

•June 11, 2026•

5 minute read

Key Takeaways

A business expense is any cost that a company or self-employed individual incurs as part of normal business operations. For tax purposes, the IRS defines deductible business expenses as costs that are both "ordinary" (common in the industry) and "necessary" (helpful and appropriate for the business).

The IRS requires substantiation of business expenses under Section 274(d): date, amount, business purpose, and relationship of parties for meals and entertainment [1].
Travel and expense (T&E) represents the second or third largest controllable spend category for most organizations, with the average per-trip cost reaching $1,128 in 2025 [2].
Navan captures business expense data at the point of transaction through corporate card integration and mobile receipt scanning, automatically categorizing costs and matching them to the appropriate policy rules.
Business meals are 50% deductible (the 100% temporary deduction for restaurant meals expired after 2022), while transportation, lodging, and business supplies remain fully deductible when properly documented [1].
The distinction between business and personal expenses matters for both tax liability and policy compliance: misclassified personal expenses create audit risk for the company and potential tax fraud liability for the individual.

What is a Business Expense?

A business expense is a cost incurred in the conduct of business operations that reduces taxable income when properly documented. The IRS defines deductible business expenses as "ordinary and necessary" costs: ordinary means common and accepted in the trade or industry, and necessary means helpful and appropriate (not indispensable) for the business [1].

For employees, business expenses are costs incurred while performing job duties that the employer either pays directly or reimburses through an accountable plan. For the employer, these reimbursements are deductible business costs. For self-employed individuals, business expenses directly reduce taxable income on Schedule C.

The concept matters beyond tax treatment. In corporate environments, business expense management encompasses how costs are authorized, documented, reimbursed, and controlled. The company's expense policy defines what qualifies as a reimbursable business expense regardless of IRS deductibility: a cost might be tax-deductible but still violate company policy.

Categories of Business Expenses

Business expenses fall into predictable categories, each with different documentation requirements and policy treatment.

Category	Examples	Deductibility	Documentation
Travel	Airfare, hotel, car rental, ground transport	Fully deductible	Receipt, business purpose, dates
Meals	Client dinners, team meals during travel	50% deductible	Receipt, attendees, business purpose
Transportation	Mileage, parking, tolls, rideshare	Fully deductible	Log or receipt, business purpose
Supplies	Office materials, software, equipment under $2,500	Fully deductible	Receipt
Professional services	Consulting, legal, accounting	Fully deductible	Invoice, contract
Communication	Phone, internet, postage	Fully deductible (business portion)	Bill showing business use percentage

Travel expenses constitute the largest and most complex category for most organizations. A single business trip generates expenses across multiple categories (air, hotel, meals, ground transport, incidentals), requires multiple receipts, and involves both policy compliance and tax substantiation rules simultaneously.

How Does Business Expense Documentation Work?

Proper documentation serves two purposes: satisfying IRS substantiation requirements for tax deductibility and meeting the company's internal audit and compliance standards.

IRS requirements under Section 274(d) mandate that travel, meal, and entertainment expenses include [1]:

Amount: The exact cost (receipts required for expenses over $75)
Time: Date and duration of the expense
Place: Where the expense occurred
Business purpose: The business reason for the expense
Relationship: For meals, who attended and their business relationship

Without this documentation, the expense loses its tax deductibility. Under an accountable plan, undocumented reimbursements must be treated as taxable income to the employee and are subject to payroll tax.

Company policy requirements often exceed IRS minimums. Most organizations require receipts for all expenses (not just those over $75), mandate specific expense categories and project codes, require pre-approval for certain expense types, and enforce spending limits that may be lower than what the IRS would allow as deductible.

Business Expense vs. Personal Expense

The line between business and personal expenses isn't always clear, particularly for travel-related costs.

Scenario	Classification	Rule
Hotel during a client meeting trip	Business	Required by the business purpose
Spa treatment at the hotel	Personal	Not ordinary or necessary
Dinner with a client discussing a deal	Business (50% deductible)	Clear business purpose and attendees
Room service while working alone	Business (50% deductible)	Meal during business travel
Extra hotel nights for sightseeing	Personal	No business purpose
Dry cleaning during a 5-day trip	Business	Ordinary during extended travel

The consequences of misclassification flow both directions. Claiming personal expenses as business costs creates tax fraud risk. Failing to claim legitimate business expenses means the company overpays taxes. Both scenarios are problems that proper expense management prevents.

Transform Your T&E Management with Navan

Make business travel work for everyone.

Get started

Managing Business Expenses at Scale

For organizations with hundreds or thousands of employees incurring expenses, the management challenge extends beyond individual documentation to program-level visibility and control.

Expense policy design. The company establishes what qualifies as a reimbursable business expense (often more restrictive than what the IRS allows), sets spending limits by category and role, and defines approval workflows. Clear policies prevent both over-spending and under-claiming.

Real-time capture. Modern expense management replaces the traditional model (save receipts, fill out forms after the trip) with real-time capture at the point of transaction. Mobile expense reporting apps photograph receipts immediately, and corporate card transactions auto-populate expense records without manual data entry.

Automated categorization. AI-based systems categorize expenses automatically based on merchant type, amount, and context. A purchase from an airport vendor during a business trip is flagged as travel incidental; the same purchase on a non-travel day requires explanation.

Policy enforcement. Automated systems validate expenses against policy rules in real time, flagging violations before submission rather than during post-trip audit. This prevents the frustration of expense rejections weeks after a trip and improves compliance rates.

Audit trail maintenance. Every expense creates a permanent record linking the transaction, receipt image, categorization, policy check result, approval decision, and payment. This audit trail satisfies both IRS substantiation requirements and internal audit standards.

Tax Deductibility Rules for Common Business Expenses

Understanding current deductibility rules helps both travelers and finance teams make informed decisions.

Business travel (air, hotel, car): 100% deductible when the primary purpose of the trip is business. Mixed-purpose trips require allocation between business and personal portions.
Business meals: 50% deductible. The 100% temporary deduction for restaurant meals (2021–2022) has expired. Meals must have a clear business purpose and documented attendees.
Mileage: Deductible at the IRS standard rate (67 cents per mile for 2025). Commuting from home to regular workplace is never deductible; travel from workplace to client sites or secondary locations is deductible.
Home office: Deductible for self-employed individuals using the simplified method ($5/sq ft, max 300 sq ft = $1,500) or actual expense method. Employees working from home cannot deduct home office expenses under current tax law.
Professional development: Conference registration, training courses, and professional certifications are fully deductible when related to the current business or profession.

Consult a tax professional for guidance specific to your situation, as rules change with tax legislation and vary by jurisdiction.

Expense Report: The document compiling individual business expenses into a submission package for approval, reimbursement, and accounting system entry.
Mobile Expense Reporting: The smartphone-based approach to capturing business expenses at the point of purchase rather than compiling them after the trip.
Compliance: The framework ensuring business expenses meet both internal policy rules and external regulatory requirements for tax deductibility.

Sources

[1] IRS, "Publication 463: Travel, Gift, and Car Expenses," 2025.

[2] GBTA, "2025 Business Travel Index Outlook," July 2025.

Frequently Asked Questions About Business Expenses

A business expense is any cost that is "ordinary and necessary" for conducting business, as defined by the IRS. Ordinary means common and accepted in your industry. Necessary means helpful and appropriate (not indispensable). Common categories include travel, meals with business purpose, office supplies, professional services, equipment, and communication costs. Personal expenses never qualify regardless of when or where they're incurred.
The IRS requires four elements for travel and meal expenses: the amount, date, business purpose, and (for meals) the names and business relationship of attendees. Receipts are required for expenses over $75. Most companies require receipts for all expenses regardless of amount, plus expense category codes, project assignments, and manager approval.
Yes, but at 50%. The temporary 100% deduction for restaurant meals (2021–2022) has expired. Business meals are deductible at 50% when there is a clear business purpose and the expense is not lavish or extravagant. Documentation must include who attended and the business topic discussed. Meals provided for the convenience of the employer on business premises have separate rules.
Navan captures business expenses automatically through corporate card integration and mobile receipt scanning. The platform categorizes transactions, validates them against company policy rules in real time, matches receipts to card charges, and routes approvals to managers. This eliminates manual expense reports and ensures proper documentation for both tax and audit purposes.
Under an accountable plan, undocumented reimbursements must be reclassified as taxable wages, creating payroll tax liability for both the employer and employee. For the company's tax return, undocumented expenses lose their deductibility, increasing taxable income. Internally, undocumented expenses are typically rejected by the finance team, delaying or denying reimbursement to the employee.
Under current U.S. tax law (since the Tax Cuts and Jobs Act of 2017), W-2 employees cannot deduct unreimbursed business expenses on their personal tax returns. This deduction was suspended through 2025 and has been extended. Only self-employed individuals and certain categories (performing artists, fee-basis state officials, Armed Forces reservists) retain this deduction.