Guide / Fundamentals
What is a business expense?
A business expense is any cost a company incurs while carrying out its operations. Office rent, employee wages, printer paper, business travel, software subscriptions — each of these is a business expense, because each is money spent to keep the business running or growing.
Understanding what counts — and how expenses are grouped — is the foundation of bookkeeping, budgeting and tax preparation. This guide covers the definition, the main types, and the ordinary-and-necessary rule that tax authorities use.
The ordinary and necessary rule
Tax authorities generally say a business expense must be ordinary (common and accepted in your trade) and necessary (helpful and appropriate for your business) to be deductible. A graphic designer buying a laptop meets the test easily; a graphic designer buying a yacht does not.
The expense must also be directly related to running the business. Personal spending — groceries, family vacations, a personal car used only for commuting — does not qualify, even if you run a business. Mixing personal and business spending is one of the most common bookkeeping mistakes small businesses make, which is why a separate business bank account is standard advice.
Operating vs non-operating expenses
Accountants split business expenses into two broad families:
- Operating expenses — the costs of day-to-day business. This includes the cost of goods sold (COGS), such as raw materials and production labor, plus selling, general and administrative (SG&A) costs: advertising, accounting and legal fees, bank charges, office supplies, payroll, rent, repairs, travel and utilities.
- Non-operating expenses — costs outside normal operations, often nonrecurring. Examples include interest paid, lawsuit settlements, business relocation or restructuring costs, inventory write-offs and losses on asset sales.
Most small businesses deal almost entirely with operating expenses, and those are the categories the ExpensePilot generator simulates.
Fixed vs variable expenses
Another useful split:
- Fixed expenses stay roughly the same each period — office rent, insurance premiums, software on annual contracts, salaries.
- Variable expenses rise and fall with activity — marketing spend, travel, office supplies, shipping, merchant fees.
- Unexpected expenses — equipment repairs, emergency replacements — deserve their own attention so they do not blindside the budget.
Categorizing this way makes it easier to forecast cash flow: fixed costs tell you your baseline, variable costs show where you can cut.
Examples of common business expenses
| Category | Examples |
|---|---|
| Advertising | Online ads, social media campaigns, business cards, flyers |
| Rent or lease | Office rent, storage space, equipment leases |
| Utilities | Electricity, water, internet, business phone |
| Office supplies | Paper, ink, pens, notebooks, cleaning supplies |
| Software | Accounting tools, project management apps, cloud storage |
| Travel | Flights, hotels, taxis, parking, mileage |
| Meals | Client meals and business travel meals (often only partly deductible) |
| Professional services | Lawyers, accountants, consultants, designers |
| Insurance | Liability, property and equipment insurance |
| Wages | Salaries, bonuses, benefits, payroll taxes |
A fuller breakdown lives in our business expense categories guide.
Why tracking matters
Recording every expense — date, amount, category, receipt — pays off in four ways: clear financial visibility into where money goes, better budget control, accurate tax filing with legitimate deductions captured, and cleaner financial reporting for lenders or investors. Businesses that review expenses monthly catch duplicate charges, unused subscriptions and creeping costs early.