What Is an Ordinary and Necessary Expense?

An ordinary and necessary expense is the standard used by the IRS to decide if a business cost can be deducted from your taxes. For an expense to be deductible, it must be both common in your line of work and helpful or appropriate for your business operations.

1. Meaning of “Ordinary and necessary expense”

The IRS breaks this down into two distinct parts:

Ordinary: An expense that is common and accepted in your particular trade or business. If most people in your industry are spending money on it, it is likely “ordinary.”
Necessary: An expense that is helpful and appropriate for your trade or business. It is important to note that an expense does not have to be “indispensable” or required for survival to be considered necessary.

In plain English, if you are buying something that helps you do your job and is a normal thing for people in your profession to buy, it generally meets this standard.

2. Why “Ordinary and necessary expense” Matters

Taxpayers should care about this term because it is the “gatekeeper” of deductions. If a cost doesn’t meet the ordinary and necessary criteria, the IRS won’t let you subtract it from your income. This means you would end up paying taxes on a higher amount of money.

Understanding this rule helps you make smarter spending decisions. When you know what qualifies, you can confidently invest in your business knowing that the cost will reduce your taxable income, effectively giving you a “discount” on those costs through tax savings.

3. How “Ordinary and necessary expense” Works

In real tax filing, this standard is highly contextual. What is ordinary for a plumber might be completely unnecessary for a web designer. For example, a plumber can deduct heavy-duty pipe wrenches because they are common and helpful in plumbing. A web designer likely cannot deduct a pipe wrench because it isn’t ordinary or necessary for building websites.

When planning your taxes, you should always ask: “Would another person in my industry agree that this is a normal business cost?” If the answer is yes, and you have the receipt to prove it, it is likely a deductible business expense. However, keep in mind that even if an expense is ordinary and necessary, it must be “reasonable” in amount—extravagant or lavish expenses are often disallowed.

4. Simple Example of “Ordinary and necessary expense”

Imagine you are a freelance writer. You pay $20 a month for a professional grammar-checking software.

Is it Ordinary? Yes, many writers use grammar tools to ensure high-quality work.
Is it Necessary? Yes, it is helpful and appropriate for improving your writing and catching errors before sending work to clients.

Since it meets both criteria, that $240 annual cost is an ordinary and necessary expense that you can deduct on your tax return.

5. Who Is Affected by “Ordinary and necessary expense”?

This standard applies to anyone who reports business-related income or expenses, including:

Self-Employed People & Freelancers: Gig workers must use this rule for every deduction on their Schedule C.
Small Business Owners: Whether operating as a sole proprietorship, LLC, or partnership.
Landlords: They use this rule for maintenance, repairs, and management costs on rental properties.
Corporations: Large and small companies alike must justify their deductions using this standard.

6. Common Mistakes Related to “Ordinary and necessary expense”

Assuming “Necessary” Means “Required”: Thinking you can only deduct things you absolutely can’t live without. If it’s just “helpful,” it still counts.
Deducting Personal Items: Trying to claim a high-end suit as a business expense because you wear it to meetings. The IRS usually considers clothing a personal expense unless it’s a specific uniform.
Extravagant Spending: Claiming a luxury first-class flight for a short trip when a standard ticket would have sufficed. The IRS expects expenses to be reasonable.
Lack of Industry Context: Failing to realize that the IRS looks at your specific niche. What’s deductible for a professional athlete (like a specialized gym membership) might not be for an accountant.

7. Forms Related to “Ordinary and necessary expense”

While there isn’t one specific form titled “Ordinary and Necessary,” this rule is the foundation for all expenses reported on:

Schedule C (Form 1040): Used by sole proprietors to list business expenses.
Schedule E: Used by landlords to list rental expenses.
Form 1120 or 1120-S: Used by Corporations to report operating costs.
Form 1065: Used by Partnerships to report business activity.

8. “Ordinary and necessary expense” vs. Related Terms

Ordinary/Necessary vs. Capital Expenditure: An ordinary expense is used up quickly (like printer paper), while a capital expenditure is for an asset that lasts years (like a car or building) and must be deducted differently.
Ordinary/Necessary vs. Personal Expense: Personal expenses are for your private life (like your home’s electricity) and are generally not deductible, even if they feel “necessary” to your well-being.
Ordinary/Necessary vs. Reasonable Expense: An expense can be ordinary and necessary but still be “unreasonable” in its cost. The IRS requires the amount to be sensible for the business purpose.

9. Related Glossary Terms

10. FAQs About “Ordinary and necessary expense”

Q: Does an expense have to be required by law to be necessary?
A: No. It just needs to be helpful and appropriate for your business. For example, advertising isn’t required by law, but it is a necessary business expense.

Q: If I buy something for my business but it doesn’t work, is it still deductible?
A: Yes. As long as the intent was for the business and the expense was ordinary and necessary at the time, the fact that the investment didn’t pay off doesn’t change its deductibility.

Q: Are commuting costs considered ordinary and necessary?
A: Generally, no. The IRS views the cost of going from your home to your regular place of work as a personal commuting expense, not a business expense.

Q: Can I deduct a gym membership if I’m a fitness influencer?
A: In this specific industry context, it might be ordinary and necessary. For most other professions, it is considered a personal health expense.

11. Final Takeaway

The “ordinary and necessary” rule is the IRS’s way of ensuring that business deductions are grounded in reality. By looking at your industry standards and the helpfulness of a purchase, you can determine what truly counts as a business write-off. Keeping this simple two-part test in mind—is it common and is it helpful?—will help you navigate your tax filings with confidence and ensure you are only paying the taxes you actually owe.

Disclaimer: This article is for general educational purposes only and should not be considered tax, legal, or financial advice. Tax rules can change, and your situation may be different. Consider consulting a qualified tax professional before making tax decisions.

What Is “Ordinary and necessary expense”?