- The single test: "ordinary and necessary"
- The deductibility checklist by category
A business can deduct any expense that is ordinary and necessary for its trade. That is the entire test, written into IRC Section 162(a). Everything else - the categories, the limits, the documentation - flows from that one sentence. This page is the practical checklist: what counts, what does not, how much, and what proof you need.
How we verified this Rules and limits on this page come from current IRC sections, IRS publications (Pub 535, Pub 463, Pub 583, Schedule C instructions), and IRS Notice 2026-10. Where blog sources disagreed with the IRS, we used the IRS.
Key Takeaways
- The deductibility standard is ordinary and necessary under IRC Section 162. "Ordinary" means common in your trade. "Necessary" means appropriate and helpful, not strictly essential.
- Section 179 lets you expense up to $2,560,000 of qualifying equipment in 2026, with phaseout beginning at $4,090,000.
- Section 195 allows a $5,000 immediate deduction for startup costs, with the remainder amortized over 180 months. Phaseout begins at $50,000.
- The 2026 IRS standard mileage rate is 72.5 cents per mile for business use, per IRS Notice 2026-10.
- Business meals are generally 50% deductible. Entertainment is not deductible at all under post-2017 rules.
- Receipts under $75 are not always required (except lodging), but a contemporaneous record of amount, date, place, and business purpose is required for every expense.
The single test: "ordinary and necessary"
IRC Section 162(a) reads: "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 Code does not define "ordinary and necessary." The definitions come from Welch v. Helvering, 290 U.S. 111 (1933) and a long line of Tax Court cases.
- Ordinary = normal and widespread in the type of business at issue. A graphic designer buying Adobe Creative Cloud is ordinary. A graphic designer buying a $50,000 fountain for the office lobby is not.
- Necessary = appropriate and helpful for the development of the business. It does not mean strictly essential. A coworking day pass is necessary even if you could technically work from home.
Most disputed deductions fail one of these two prongs, usually "ordinary." If you cannot point to other businesses in your trade making similar purchases, the IRS will challenge the deduction.
The deductibility checklist by category
This table maps the major categories every U.S. small business should consider. Lines refer to Schedule C (Form 1040) for sole proprietors and single-member LLCs.
| Category | Schedule C Line | Deductibility | Key Rule or Limit |
|---|---|---|---|
| Advertising and marketing | Line 8 | 100% | Includes online ads, print, business cards, website costs |
| Car and truck expenses | Line 9 | 100% of business use | Standard mileage 72.5c/mi (2026) or actual expenses |
| Commissions and fees | Line 10 | 100% | Payment processing, sales commissions, broker fees |
| Contract labor (1099) | Line 11 | 100% | 1099-NEC required if you pay any contractor $600+/yr |
| Depreciation and Section 179 | Line 13 | 100% (with limits) | Section 179 cap: $2,560,000 in 2026 |
| Employee benefits | Line 14 | 100% | Health, retirement contributions for employees |
| Insurance (other than health) | Line 15 | 100% | General liability, E&O, business property |
| Interest (business) | Line 16 | 100% | Business loans, business credit card interest |
| Legal and professional services | Line 17 | 100% | Lawyers, accountants, consultants, tax prep |
| Office expense | Line 18 | 100% | Postage, stationery, small office items |
| Rent or lease (other than vehicles) | Line 20b | 100% | Office rent, equipment leases, coworking |
| Repairs and maintenance | Line 21 | 100% | Restoration to working condition only, not improvements |
| Supplies | Line 22 | 100% | Consumed within one year |
| Taxes and licenses | Line 23 | 100% | Excludes federal income tax |
| Travel | Line 24a | 100% | Must be away from tax home overnight |
| Meals | Line 24b | 50% (most) | 100% in narrow cases per IRC Section 274 |
| Utilities | Line 25 | 100% of business portion | Internet, phone, electricity at business location |
| Wages (W-2 employees) | Line 26 | 100% | Reasonable compensation only |
| Home office (simplified) | Line 30 | $5/sq ft, max 300 sq ft | Cap: $1,500. See home office guide |
For each line, the underlying test is still "ordinary and necessary." Listing an expense on the right line does not make it deductible if it fails Section 162.
What is NOT deductible
Plenty of expenses look deductible but are not. The most common misses:
- Entertainment. Sporting events, concerts, club dues for entertainment purposes. Disallowed under IRC Section 274(a) since the 2017 Tax Cuts and Jobs Act.
- Commuting from home to a regular workplace. Mileage between business locations or to client sites is deductible; commuting is not.
- Federal income tax paid. Other federal taxes (employer FICA, federal unemployment) are deductible.
- Personal expenses, even if charged to a business card. The card the expense ran through does not change the substance.
- Penalties and fines paid to a government for violation of law.
- Political contributions of any kind.
- Lobbying expenses for influencing legislation, with narrow exceptions for local lobbying.
- Health club dues unrelated to a qualified medical expense.
- Cost of getting an initial professional license (e.g., the bar exam fee, the CPA exam fee). Renewal fees are deductible.
The big four with specific dollar limits
Most categories above are deductible at 100%. Four categories have specific limits that change every few years and are worth knowing in detail.
Section 179: Equipment expensing
IRC Section 179 lets a business deduct the full cost of qualifying equipment in the year placed in service, rather than depreciating over years.
For tax year 2026:
- Maximum deduction: $2,560,000
- Phaseout threshold: $4,090,000 (deduction reduced dollar-for-dollar above this)
- Complete phaseout: $6,650,000
Source: Section179.org 2026 limits. The figures match IRS inflation adjustments.
Qualifying property: tangible personal property (machinery, computers, furniture, off-the-shelf software), most business vehicles, and certain real property improvements like roofs, HVAC, and security systems on nonresidential real property.
The deduction is limited to taxable income; you cannot use Section 179 to create or increase a loss.
Section 195: Startup costs
IRC Section 195 allows new businesses to deduct startup costs incurred before the business begins operations.
- Immediate deduction: $5,000 in the year operations begin
- Phaseout: $5,000 is reduced dollar-for-dollar when startup costs exceed $50,000
- Complete phaseout: $55,000 (no immediate deduction)
- Remainder: amortized over 180 months (15 years)
Qualifying startup costs include investigatory expenses (market surveys, feasibility studies), pre-launch employee training, advertising before opening, and professional fees related to forming the business.
The trap: many new founders spend more than $55,000 before launch, miss the $5,000 immediate write-off entirely, and stretch the deduction across 15 years. Tracking total startup spend against the $50,000 threshold is one of the highest-ROI bookkeeping moves a new business can make.
Standard mileage rate
IRS Notice 2026-10 sets the 2026 rates:
- Business: 72.5 cents per mile (up 2.5 cents from 2025)
- Medical or moving (qualified active-duty military only): 20.5 cents per mile
- Charitable: 14 cents per mile
You may choose the standard mileage rate or actual vehicle expenses. To use the standard rate, you must elect it in the first year the vehicle is placed in business service. Once you use actual expenses (including depreciation), you cannot switch back for that vehicle.
For deeper detail on mileage logs, see how to track mileage for business.
Meals (50% rule)
IRC Section 274(n) limits most business meal deductions to 50% of the cost. Both food and beverages count.
A business meal is deductible when:
- The taxpayer or an employee is present
- The meal is not lavish under the circumstances
- The meal is associated with a substantiated business activity
Narrow exceptions are 100% deductible:
- Meals provided to the general public (a free customer event)
- Meals taxable as wages to the recipient
- Reimbursed meals to employees under an accountable plan
- Office snacks and beverages provided to employees (previously 100% deductible; now 50% through 2025, scheduled 0% after)
Entertainment with a meal: you can still deduct 50% of the meal cost if it is separately stated and not lavish; the entertainment portion remains nondeductible.
Documentation: what the IRS actually requires
IRC Section 274(d) sets the substantiation standard for travel, meals, gifts, and listed property. The substantiation rules from Publication 463 apply to all business expenses by extension.
For each expense you must be able to show:
- Amount (cost)
- Time (date)
- Place (location for travel and meals)
- Business purpose (why it relates to your trade)
- Business relationship (for entertainment and gifts, who was present)
Receipts are required for:
- Lodging expenses, always, regardless of amount
- Other expenses of $75 or more (the so-called "$75 receipt rule")
- Listed property (vehicles, certain electronics): always
For expenses under $75 other than lodging, you do not need a paper receipt - but you do need the record. Most cardholders just keep every receipt, since the marginal cost of doing so is zero with mobile receipt capture.
Publication 583 sets the retention requirement: generally three years from the return due date, longer for substantial understatement (six years) or claims of loss from worthless securities or bad debt (seven years).
Deductions sole props miss most often
Across thousands of Schedule C returns reviewed by tax-prep apps and CPAs, the same deductions get missed year after year. The pattern is consistent enough to publish.
- Self-employed health insurance. A self-employed taxpayer can deduct 100% of qualifying health insurance premiums for themselves, spouse, and dependents - as an adjustment to income (not on Schedule C), per Section 162(l). Limited by net earnings from self-employment.
- Retirement contributions. SEP-IRA contributions up to 25% of net self-employment earnings (capped at ~$70,000 for 2026 per IRS inflation adjustments); Solo 401(k) contributions up to a similar limit.
- Quarterly estimated tax payments. Not deductible federally (federal income tax never is), but state estimated payments are deductible up to the SALT cap. The deduction goes on Schedule A, not Schedule C.
- Section 199A QBI deduction. Up to 20% of qualified business income for pass-through entities (sole prop, partnership, S corp), subject to income limits. Calculated on Form 8995 or 8995-A; not directly on Schedule C.
- Education that maintains or improves skills required in your current trade. Not education that qualifies you for a new trade or business.
- Subscriptions to industry publications, professional associations, and trade journals.
- Bank fees on business accounts and merchant processing fees.
- Mileage to the post office, bank, supplier, or client site. All counts. Only home-to-office commuting does not.
- Cell phone business-use portion. Deductible at the business-use percentage if not provided by an employer.
Entity-specific notes
Sole proprietor and single-member LLC
Files Schedule C. All deductions above apply. The owner cannot pay themselves a W-2 salary - net Schedule C profit flows through to the owner's 1040 and is subject to 15.3% self-employment tax plus income tax.
Multi-member LLC (taxed as partnership)
Files Form 1065 and issues K-1s. Most categories above apply at the partnership level. Partners report their share on Schedule E and may deduct unreimbursed partnership expenses if required by the partnership agreement.
S corporation
Files Form 1120-S. Shareholders must take reasonable compensation as W-2 wages before any distributions. Most deduction categories above apply at the corporate level, including a separate Schedule for shareholder reimbursements under an accountable plan.
The S corp's most important deduction tactic is the accountable-plan reimbursement of shareholder expenses (home office, mileage, cell phone). Done correctly, the corporation deducts the reimbursement and the shareholder receives the cash tax-free. Done incorrectly, the reimbursement becomes additional wages.
C corporation
Files Form 1120. Most categories above apply, with one key difference: a C corp can deduct fringe benefits (health insurance, group term life insurance, education assistance) for shareholder-employees that pass-throughs cannot. The double-taxation tradeoff is usually worse than this is worth for small businesses.
Audit triggers: what raises real risk
IRS Data Book 2023 (the latest published) shows audit rates under 1% for most individual returns and lower than that for most categories of Schedule C filers. Audit risk on a specific deduction is not the right framing - the IRS audits returns, not categories. What raises risk on a return:
- Large deductions disproportionate to revenue. A $40,000 meals deduction on $80,000 revenue draws review.
- Round numbers. A $5,000 even deduction with no underlying detail looks like a guess.
- Hobby loss patterns. Reporting losses for 3+ consecutive years in a low-revenue Schedule C activity invites a "is this really a business" review.
- Schedule C with no 1099-K or 1099-NEC reported income that should match third-party reports.
- Mismatch between 1099-NEC paid to contractors and Line 11. The IRS cross-checks these.
- Cash-heavy businesses (restaurants, contractors, salons) with low reported revenue relative to industry averages.
The risk-reducing pattern is unsurprising: keep separate business accounts, document every deduction contemporaneously, file 1099-NEC forms when required, and avoid round numbers.
A 12-step year-end checklist
- Reconcile bank and card statements with your bookkeeping through December 31.
- Verify every category has at least one supporting document (receipt, invoice, log).
- Run a mileage log review against your calendar - every business trip logged?
- Confirm home office square footage and method (simplified vs actual). Decide before filing.
- Tally startup costs if business launched this year. Apply the $5,000 immediate deduction.
- Total Section 179 purchases and verify they are under the $2,560,000 cap.
- Categorize contract labor. Anyone paid $600+? File 1099-NEC by January 31.
- Identify 50% vs 100% meals. Separate any 100%-eligible meals into a sub-account.
- Pull self-employed health insurance premium total for the Schedule 1 adjustment.
- Calculate retirement contribution (SEP-IRA, Solo 401(k)) before the funding deadline.
- Project QBI deduction under Section 199A.
- Lock the records in cloud storage with copies of receipts, mileage logs, and bank statements. Keep at least 3 years; 7 if you have any unusual positions.
When this guide isn't for you
This checklist is built for U.S. small businesses filing Schedule C, Form 1065, Form 1120-S, or Form 1120. Skip this guide if:
- You file outside the U.S. Deduction rules differ in every jurisdiction. The "ordinary and necessary" test is specific to U.S. tax law.
- You file a not-for-profit return. Section 162 does not apply to Section 501(c) organizations the same way.
- Your business is purely an investment vehicle (rental real estate, day trading). Different sections apply: 469 (passive activity), 1031 (like-kind exchange), 1402(a) (SE tax exclusions).
- You expect anything beyond moderate IRS scrutiny. Use a CPA. This page summarizes general rules; positions on edge cases require professional advice.
- You are in a heavily-regulated industry (cannabis under Section 280E, illegal activities). The deductibility rules change materially.
Frequently Asked Questions
Which expenses are 100% deductible?
Most ordinary business expenses are 100% deductible: advertising, rent, utilities, supplies, contract labor, professional services, software, and most travel. The categories with partial deductibility are meals (50%), gifts to clients ($25 per recipient per year), and certain employee fringe benefits. Entertainment is not deductible at all under post-2017 rules.
How much can you write off on taxes for business expenses?
There is no aggregate cap. The limit is per-category: Section 179 equipment up to $2,560,000 in 2026, Section 195 startup costs at $5,000 immediate plus 180-month amortization above $50,000, meals at 50%, gifts at $25 per recipient. Beyond those, any ordinary and necessary expense is deductible in full - even if it produces a loss that offsets other income.
What deductions can you claim as a business expense?
Any expense that is ordinary (common in your trade) and necessary (appropriate and helpful), per IRC Section 162. The Schedule C categories above are the IRS's default groupings: advertising, vehicle, contract labor, depreciation, insurance, interest, legal/professional, office, rent, repairs, supplies, taxes/licenses, travel, meals, utilities, wages.
Do I need a receipt for every business expense?
No. Receipts are required for lodging always and for any other expense of $75 or more. For expenses under $75, you still need a contemporaneous record (date, amount, place, business purpose) - but not the paper receipt itself. Most businesses keep every receipt anyway since mobile capture has made the marginal cost zero.
Can I deduct expenses I paid before the business officially started?
Yes, under Section 195. The first $5,000 of qualified startup costs is deductible in the year the business begins operations. Anything above $5,000 (and below the $50,000 phaseout) is amortized over 180 months. Above $55,000 in startup costs, the immediate deduction is fully phased out and the entire amount is amortized.
How long do I need to keep business expense records?
Generally three years from the date you filed the return, per IRS Publication 583. Six years if you understated income by 25% or more. Seven years for claims of loss from worthless securities or bad debt. Indefinitely for records relating to depreciation of property you still own. Most businesses default to seven years for simplicity.
Bottom line
The IRS's standard for deductibility is broad. Most expenses a working business incurs are deductible. The hard part is documentation, not eligibility.
Three habits cover 90% of what matters:
- Separate accounts. A dedicated business checking account and card. Personal cards or accounts are not disqualifying, but they make audits harder. See business credit card vs debit card.
- Contemporaneous records. Capture the receipt and the business purpose at the time of the expense, not at year-end. An expense tracking app handles this automatically.
- Quarterly review. Reconcile bank statements to bookkeeping every quarter, not annually. Errors are 4x cheaper to fix three months later than twelve months later.
Try Billed free to invoice clients, track receivables, and keep the income side of your books as clean as your expense side.