Business Tax Deductions You Are Probably Missing

Business tax deductions reduce the income you pay tax on, and the ones owners miss are almost never exotic. They are ordinary costs that got paid from the wrong card, recorded in the wrong category, or never recorded at all because nobody thought of them as a business expense.

That is the whole problem in one sentence. A deduction you are entitled to and did not claim is money you handed over voluntarily, and nothing in the filing process will tell you it happened. Your accountant can only deduct what your records show. Software categorizes what you feed it. If the receipt never made it into the system, the deduction does not exist.

This is the line-by-line list: what each deduction covers, what it is worth under 2026 rules, and the specific record that proves it. The deductions are grouped by why they get missed, because the fix is different in each case.

The Bottom Line

• The most commonly missed deductions are vehicle costs, the home office, a portion of the phone and internet bill, and the 20% pass-through deduction, which is claimed on the return rather than from a receipt.
• The 2026 business standard mileage rate is 72.5 cents per mile, up 2.5 cents from 2025 (IRS). For a van covering 20,000 business miles, that is a $14,500 deduction that exists only if the miles were logged.
• The home office simplified method is $5 per square foot up to 300 square feet, capping at $1,500 a year, and requires no expense tracking at all.
• Section 199A lets eligible owners deduct up to 20% of qualified business income, with 2026 phase-outs starting at $200,000 single and $400,000 joint (SD O’Connell CPA).
• Mixing personal and business spending on one card is the single biggest cause of lost deductions. Separate accounts recover more money than any individual line item on this list.

Vehicle and delivery costs, the biggest miss

Vehicle expenses are the largest deduction most delivery-side businesses underclaim, and they are underclaimed for a boring reason: the log.

You choose one of two methods per vehicle. The standard mileage rate multiplies business miles by a single IRS figure meant to cover fuel, insurance, repairs, maintenance, tires, registration and depreciation. For 2026 that figure is 72.5 cents per mile (IRS). The actual expense method deducts the business-use percentage of what the vehicle really costs.

Standard mileage tends to win for cheap vehicles covering a lot of ground. Actual expenses tend to win for an expensive, heavy, hard-worked vehicle, because a refrigerated box truck’s real running costs outrun any per-mile average. You cannot use both for the same vehicle in the same year, and the method chosen in a vehicle’s first year constrains what you can switch to later.

The record that matters: a contemporaneous mileage log with date, miles and business purpose for each trip. Not a year-end estimate, not an average week multiplied by 52. This is the deduction most often reduced on examination, and always for the same reason.

Beyond the vehicle itself, these get missed routinely:

• Parking and tolls incurred on delivery runs, deductible on top of the standard mileage rate rather than included in it.
• Trips that do not feel like deliveries: driving to a supplier, to the bank, to a packaging wholesaler, to a customer site to quote a job. Those are business miles.
• Route equipment: shelving and bulkheads, insulated containers, hand trucks, scanners, cargo liners, and the routing or dispatch software that plans the stops.
• Driver labor, whether wages for employees or contractor payments, along with the payroll taxes and benefits attached to employees.

A vehicle or heavy equipment purchase is a different kind of deduction, because you can often take the whole thing in year one instead of depreciating it. In 2026 a vehicle over 6,000 pounds carries a $31,300 Section 179 cap, with 100% bonus depreciation available above that ceiling (Crest Capital). Which year you want that deduction in is a planning question rather than a filing one, and our quarter-by-quarter guide to business tax planning covers how to pick the year and why ordering in October beats ordering in December.

Home and workspace deductions owners skip

Owners who run the business from a kitchen table or a back office frequently claim nothing here, usually from a belief that the home office deduction invites scrutiny. It does not, provided the space qualifies.

The test is regular and exclusive business use. A corner of a room used only for the business qualifies. A dining table that hosts dinner does not.

Two methods:

• Simplified: $5 per square foot, up to 300 square feet, capping at $1,500 a year. No expense tracking, no depreciation calculation, nothing to substantiate beyond the square footage.
• Regular: the business-use percentage of actual home costs: mortgage interest or rent, utilities, insurance, repairs, plus depreciation. More work, usually a larger number for a larger space.

Adjacent spaces get forgotten entirely. If you rent cold storage, a commissary kitchen slot, a garage bay for the vans or a self-storage unit for packaging, that rent is a straightforward business expense. So is the business portion of a home internet connection and a mobile phone, prorated honestly: a 70% business phone is a 70% deduction, not an all-or-nothing choice.

Deductions hiding in ordinary monthly bills

This group is missed because the charges are small, automatic, and never looked at again.

• Merchant processing and payment fees: a business taking $400,000 a year through cards at roughly 2.9% is paying over $11,000 in processing. Fully deductible, and frequently netted silently out of deposits so it never appears as an expense at all.
• Bank fees, wire fees and account charges on business accounts.
• Software subscriptions: accounting, routing, scheduling, point of sale, design tools, email, cloud storage, website hosting.
• Business insurance premiums: general liability, commercial auto, property, workers’ compensation, cargo and spoilage cover.
• Interest on business borrowing: interest on a business loan, a credit line draw or a business credit card balance is deductible even though the principal is not. If you are weighing a revolving facility against other funding, our breakdown of how a business line of credit works and what it actually costs sets out the interest math.
• Professional fees paid to an accountant, bookkeeper, lawyer or consultant for work relating to the business.
• Dues, licenses and subscriptions: trade association membership, business licenses, health permits, industry publications.
• Continuing education that maintains or improves skills used in the current business, including courses, certifications and conference fees.

The record that matters: a business bank account and a business card, used for business only. Every item above is captured automatically when the spending runs through dedicated accounts, and hunted for manually when it does not.

Inventory, spoilage and bad debt

Businesses that hold physical stock have deductions that service businesses never think about, and they are easy to lose in the gap between a count sheet and a tax return.

Cost of goods sold is the obvious one and is usually handled correctly. The ones that slip:

• Spoilage and shrinkage: product thrown out because it did not sell, got damaged in transit or missed its window is a cost of doing business, and for a bakery or florist it can be material. Document the write-off when it happens, not at year end from memory.
• Samples and donated product: goods given to prospects, dropped into gift bags, or donated are generally deductible at cost.
• Bad debt, if you are on the accrual basis. An invoice recognized as income and never collected can be written off. Cash-basis businesses never recognized it, so there is nothing to deduct.
• Packaging and shipping supplies: boxes, insulated liners, ice packs, labels, tape, branded bags.

Uncollected invoices raise a second question beyond the deduction, which is how long your money sits in someone else’s hands before it comes back. That is a cash problem rather than a tax one, and how to shorten the cash conversion cycle through receivables, inventory and payables is where it gets dealt with properly.

Deductions that are claimed on the return, not from a receipt

These are the ones no bookkeeping discipline will surface, because there is nothing to record. They exist only if someone claims them.

The pass-through deduction. Section 199A lets eligible owners of sole proprietorships, partnerships and S-corps deduct up to 20% of qualified business income. For 2026 the phase-out ranges sit at $200,000 to $275,000 for single filers and $400,000 to $550,000 for joint filers, with a $400 minimum deduction where QBI exceeds $1,000, and it is available whether or not you itemize (SD O’Connell CPA). On $90,000 of qualified business income, that is an $18,000 reduction in taxable income with no transaction behind it.

Startup costs. A business in its prelaunch stage or first year can claim up to $5,000 of startup expenses, with the rest amortized (US Chamber of Commerce). Owners in year two who never claimed it often did not know the category existed.

Half of self-employment tax. Sole proprietors pay 15.3% self-employment tax and deduct half of it against income. Tax software handles this automatically; owners doing their own arithmetic sometimes do not.

Retirement contributions. A SEP-IRA, SIMPLE or solo 401(k) contribution reduces taxable income in the year it is made, and the deadlines extend past December 31 for some plan types. This is the largest single lever available to a profitable owner with no spending to accelerate.

Health insurance premiums. A self-employed owner can generally deduct premiums paid for themselves and their family, subject to limits.

Deductions with rules worth knowing before you claim them

Three categories are legitimate but partial, and claiming them at full value is a common error.

• Business meals are 50% deductible, and only when the meal involves a client, prospect, vendor or business partner and business is discussed (Rippling). Your own lunch between stops is not deductible. Food provided for a staff meeting is treated differently again.
• Entertainment is not deductible: tickets, golf and outings were removed. If a meal is bundled into an entertainment ticket, only a separately stated food charge survives.
• Advertising and marketing are fully deductible: digital and print ads, billboards, content, signage, vehicle wraps, photography. Sponsorship with a personal benefit attached does invite questions. Keep the business purpose written down.

Build the system once, then stop missing things

Every deduction on this list reduces to one of two failures: the money moved through a personal account, or the activity left no record. Both are fixable in an afternoon.

• Separate the accounts: a business checking account and a business card, used only for the business. This recovers more deductions than any single item above, and it also stops the reverse problem of business accounts quietly funding personal spending, which is how owners end up carrying card balances that cost more than they realize. (If that has already happened, the exit is usually consolidation rather than minimum payments; this guide to using a personal loan to clear credit card debt explains the tradeoff.)
• Automate the mileage log: an app that records trips from the phone, categorized weekly. This is the single highest-value habit for a business that delivers.
• Photograph receipts at the point of sale: cash purchases and small supply runs are where documentation disappears.
• Reconcile monthly, not annually: miscategorized expenses are easy to fix six weeks later and nearly impossible to reconstruct fourteen months later.
• Review the category list once a year against a list like this one. A deduction you have never claimed will not appear in your books on its own.

Frequently asked questions

What is the most commonly missed business tax deduction?

Vehicle expenses, because they depend on a contemporaneous mileage log rather than a receipt. The home office deduction and the business portion of phone and internet bills are close behind, and the 20% pass-through deduction is the most valuable one that gets missed entirely because there is no transaction to prompt it.

Can I deduct expenses from before the business was officially registered?

Up to $5,000 of startup costs can be claimed in the first year, with the remainder amortized (US Chamber of Commerce). Market research, legal and registration fees, and initial equipment purchases usually qualify.

How long do I need to keep receipts for business tax deductions?

Three years from the filing date covers the normal examination window, and seven years is the common conservative practice. Records supporting depreciation on a vehicle or equipment need to survive as long as the asset is on the schedule, which can be well past seven years.

Do I need receipts for every expense?

You need records adequate to substantiate the amount, date and business purpose. Bank and card statements combined with a clear description carry most routine expenses; vehicle use, travel and meals are held to a higher standard and want the specifics written down at the time.

Is it better to take the standard mileage rate or actual vehicle expenses?

Run both for a year before deciding. Standard mileage usually produces more on an inexpensive, high-mileage vehicle; actual expenses usually produce more on an expensive, heavy, hard-worked one. Note that the method you pick in the vehicle’s first year limits your later options, so it is worth doing the arithmetic rather than defaulting.

Start with the four that are worth the most

Claim the mileage, the home office, the prorated phone and internet, and the pass-through deduction. Those four cover most of the gap for a typical owner-operated business, and three of the four cost nothing but a record.

Then separate your accounts, if they are not already, and set a monthly reconciliation date. Next year’s deductions are decided by what your books capture over the next twelve months, not by how carefully anyone reads the return in April.