Business Credit Cards and Taxes: A Reference

Internal Revenue Code Section 162 is the foundational provision allowing the deduction of business expenses. It states, with the surrounding subsections setting limits and exceptions, that "there shall be allowed as a deduction all the ordinary and necessary expenses paid or incurred during the taxable year in carrying on any trade or business." The two operative tests are "ordinary and necessary" and "in carrying on any trade or business."

"Ordinary" means common and accepted in the trade or business. "Necessary" means helpful and appropriate, not strictly indispensable. The standard is not a high bar in most cases; it filters out expenses that are personal in nature, capital in nature (which are subject to depreciation rather than direct deduction), or unrelated to the trade or business.

For years, IRS Publication 535 (Business Expenses) was the consolidated reference that walked through the test by category. The IRS discontinued Publication 535 after the 2022 tax year; the 2022 edition is the last revision. The guidance now lives in topic-specific publications, mapped by the IRS Guide to Business Expense Resources. The general small-business starting point is now Publication 334 (Tax Guide for Small Business), with travel and car expenses in Publication 463 and depreciation in Publication 946. The ordinary-and-necessary test in Section 162 is unchanged; only the reference document moved.

What qualifies as a business expense when charged on a business card

The business card is a payment instrument; the deductibility of the expense is determined by the nature of the expense, not by how it is paid. The major deductible expense categories enumerated in Publication 334 and related publications include:

• Supplies and materials. Consumed in the course of business; deductible in the year incurred.
• Utilities and rent. Office space, electricity, water, internet, telecom; ordinary and necessary in nearly all businesses.
• Advertising and marketing. Reasonable advertising expenses are deductible; lavish or extravagant advertising can be challenged.
• Travel. IRS Publication 463 is the consolidated reference. Receipts are required for expenses over $75; contemporaneous business-purpose notes are required for travel and entertainment expenses.
• Meals. Generally 50 percent deductible under IRC Section 274(n), with specific exceptions and elevated percentages for certain categories. Publication 463 walks through the rules.
• Equipment. Capital expenditures over a threshold are subject to depreciation rather than immediate deduction. The Section 179 expense election permits immediate deduction of qualifying equipment up to the annual cap, which has changed several times in recent years; the IRS publishes the current limit annually.
• Professional services. Legal, accounting, and consulting fees incurred in carrying on the trade or business are deductible.
• Insurance. Business liability, commercial property, and most other business insurance is deductible.

Spend in any of these categories charged to a business credit card is potentially deductible if the underlying transaction meets the ordinary-and-necessary test. The card statement is part of the substantiation, but it is not by itself sufficient documentation; receipts and business-purpose notes are required for many categories under Publication 463 and Publication 583.

Vehicle costs: the actual cost method vs the standard mileage rate

Vehicle expenses are a common source of confusion because the Internal Revenue Code permits two distinct ways of deducting them, and the choice has recordkeeping consequences for what a business card statement needs to support. IRS Publication 463 is the governing reference.

The actual expense method (often called the actual cost method) deducts the real costs of operating the vehicle for business: gas, oil, repairs, maintenance, tyres, insurance, registration, lease payments, tolls and parking, and depreciation including the Section 179 expense election where it applies. Each cost is multiplied by the business-use percentage of the vehicle. Fuel, repairs, and similar charges paid on a business card are part of the substantiation, but Publication 463 still requires the underlying records (the receipt and the business-purpose note), not the statement alone.

The standard mileage rate is the alternative: a single per-mile figure that stands in for all operating costs, multiplied by business miles driven. The rate is 72.5 cents per mile for 2026 (Notice 2026-10), up from 70 cents in 2025. A contemporaneous mileage log is the substantiation. A taxpayer choosing the standard mileage rate cannot also deduct the individual operating costs that the rate already covers; tolls and parking remain separately deductible under either method.

The methods are mutually exclusive for a given vehicle in a given year, and the rules on switching between them (particularly after claiming depreciation or the Section 179 deduction) are specific. Publication 463 walks through the eligibility and switching constraints.

Business credit card interest is deductible

IRC Section 163 allows the deduction of "all interest paid or accrued within the taxable year on indebtedness." Section 163(h) excludes most personal interest from deduction for individuals (with carve-outs for qualified residence interest and a few other categories), but business interest is generally allowed under the broader Section 163 rule, subject to the Section 163(j) limitation that applies to certain larger businesses.

Interest accrued on a business credit card that funds business expenses is therefore deductible in the year paid for cash-basis taxpayers, or accrued for accrual-basis taxpayers. The cardholder should track interest separately from principal payments in accounting; the monthly statement provides the breakdown.

Where a business card has mixed personal and business spend (a substantiation concern in itself), the interest also has to be allocated proportionally. IRS regulations on tracing interest to its underlying use make the allocation defensible if done correctly and indefensible if not. Treasury Regulations Section 1.163-8T provides the interest-tracing rules.

Recordkeeping obligations

IRS Publication 583 (Starting a Business and Keeping Records) sets out the recordkeeping framework. The business is required to keep records sufficient to substantiate income and expenses for the duration of the statute of limitations on assessment, which is three years from filing in most cases, six years for substantial understatement of income, and unlimited for fraudulent returns.

Sufficient records typically include:

• Receipts for individual expenses (required for amounts above the de minimis threshold)
• Bank and credit card statements
• Cancelled checks and electronic payment records
• Invoices and contracts
• Mileage logs for business vehicle use
• Travel and entertainment expense logs with business-purpose notes

IRS Publication 463 specifies the receipt requirement at $75 for travel and entertainment expenses. For lodging, receipts are required regardless of amount. Per-diem methods are an alternative for some categories; Publication 463 walks through the calculations.

The problem with mixed personal and business spend

When a single card is used for both personal and business expenses, substantiation at audit becomes difficult. The IRS is not required to accept the cardholder's after-the-fact allocation of mixed spend. The auditor may disallow expenses that cannot be cleanly tied to a business purpose, may apply a haircut to mixed-use categories, or may demand reconstruction of records that the cardholder may not be able to produce years later.

Beyond the audit risk, mixed spend is operationally expensive. Each statement requires the bookkeeper or owner to read every transaction and allocate it to personal or business. The interest accrued on the card requires allocation under the tracing regulations. The credit-card-rewards taxability question (covered in the rewards and taxes entry) becomes harder to answer because the rewards may be partially business-rebate and partially personal.

What to do if you already have mixed spend

Three steps to clean up:

Reconstruct records for the affected period. Pull the card statements, identify each transaction as personal or business, attach receipts where available, and make a contemporaneous note where receipts are not available explaining the business purpose. The reconstruction is imperfect substantiation but it is materially better than no documentation.

Annotate the books to reflect the cleanup. Where accounting software is in use, code the personal transactions to an owner-draw or shareholder-distribution account and the business transactions to the appropriate expense categories. The accounting record should match the underlying allocation.

Transition to separated cards going forward. Close the mixed-use pattern by opening a dedicated business card and a dedicated personal card, then routing all spend through the appropriate one. The transition immediately stops the substantiation problem from compounding.

For ongoing accounting hygiene, the accounting-software reference site covers the platform options that automate the categorisation step. Substantiation is fundamentally a record-keeping problem, and clean records make the audit outcome materially more defensible.

Not tax advice

This page summarises publicly available IRS guidance for educational purposes. It does not constitute tax advice for any specific taxpayer. The interaction between credit-card spend, business deductions, and the cardholder's overall tax position is fact-specific. A licensed CPA or tax attorney can advise on the application of these rules to a specific situation.