Small Business Tax Write-Offs in Canada: The 2026 Checklist

Every business owner has heard someone at a barbecue say "just write it off." Most of the time, the person saying it could not explain what a write-off actually does. So before the checklist, a quick reality check, because understanding the mechanics is what separates owners who save real money from owners who get reassessed.

How do tax write-offs actually work?

A deduction reduces your taxable income, not your tax bill. If your business earns $100,000 and you deduct $10,000 of legitimate expenses, you pay tax on $90,000. The saving is the deduction multiplied by your tax rate.

For an incorporated Canadian small business, the combined federal and Ontario small business rate is 11.2% as of July 1, 2026 (9% federal plus Ontario's newly cut 2.2%). So a $1,000 deduction saves about $112. For a sole proprietor, business income is taxed at your personal marginal rate, which climbs much higher, so the same $1,000 deduction can save several hundred dollars. That difference is one reason the incorporation decision changes your whole tax picture.

Two rules govern everything below. The expense must be incurred to earn business income, and it must be reasonable. A $40 client lunch is reasonable. A $4,000 one is a conversation with an auditor.

What can a small business write off in Canada?

Here is the 2026 checklist. Nearly every line depends on the expense actually being recorded in your books, which we will come back to.

A few of these deserve a closer look, because they are the ones the CRA reviews most often.

How does the home office deduction work?

You can deduct home workspace costs if the space is your principal place of business, or you use it regularly and exclusively to meet clients, patients, or customers.

The math is proportional. If your office is 150 square feet of a 1,500 square foot home, you deduct 10% of eligible home costs: utilities, internet, rent if you lease, and for homeowners a share of property taxes and home insurance. Run the percentage honestly. Claiming 40% of your home as "office" is a classic review trigger.

One more nuance: home office expenses cannot create or increase a business loss. Unused amounts carry forward to future years, so track them even in a slow year.

How do you write off vehicle expenses?

You deduct the business-use percentage of your vehicle costs, and the CRA expects you to prove that percentage with a kilometre logbook: date, destination, purpose, and distance for business trips, plus total kilometres for the year.

Drive 20,000 km in a year, 8,000 of them for business, and 40% of your fuel, insurance, repairs, and licensing becomes deductible. Depreciation on the vehicle itself is claimed separately through capital cost allowance, which spreads the cost over several years rather than deducting the purchase all at once.

No logbook means no defensible number, and "I drive a lot for work" has never once impressed an auditor. A logbook app on your phone solves this permanently.

Can you pay family members and deduct it?

Yes, and for many family-run businesses it is one of the most useful deductions on the list. Salaries paid to a spouse or child are deductible under the same two conditions as any expense: the work is real, and the pay is reasonable for what was actually done.

Reasonable means what you would pay a stranger for the same job. If your teenager manages your social media and files invoices five hours a week, pay the going rate for that work, run it through payroll properly, and keep a simple record of what they did. Done right, income shifts from your higher tax rate to their lower one, and the business deducts every dollar.

Done wrong, it unravels fast. A $50,000 "office manager" salary to a spouse who never touches the business is the kind of deduction the CRA denies while leaving the recipient taxed on the income anyway, the worst of both worlds. Keep timesheets or task records, pay by traceable transfer rather than cash, and issue the proper slips.

What about the timing of big purchases?

Not every business cost is deducted in the year you spend it. Equipment, computers, vehicles, and furniture are capital assets: instead of writing off the full price at once, you deduct a portion each year through capital cost allowance (CCA). The classes and rates vary by asset type, which is precisely the kind of detail worth handing to your accountant rather than guessing.

Two practical takeaways. First, a December equipment purchase can still generate a partial-year claim, so year-end timing conversations are worth having before December 31, not after. Second, CCA is optional in any given year; skipping it in a loss year and saving it for a profitable one is a legitimate planning move that owners doing their own returns almost always miss.

What can you not deduct?

The list of famous non-deductions, each one requested weekly by hopeful owners everywhere:

• Regular clothing. Suits, dresses, and anything you could wear outside work are personal, even if you only bought them for client meetings. Actual uniforms and safety gear are different.
• Commuting. Driving from home to your regular place of work is personal travel. Travel between work locations or to client sites is business.
• Personal meals. Lunch at your desk is not a business meal. The 50% rule applies to meals with a genuine business purpose, not to feeding yourself.
• Life insurance premiums. Usually not deductible, with narrow exceptions such as policies assigned as collateral for certain business loans.
• Golf and club memberships. Explicitly blocked by the Income Tax Act, no matter how much business happens on the back nine.
• Fines and penalties. Parking tickets and CRA penalties stay on your side of the ledger.

What records does the CRA expect you to keep?

Keep your receipts, invoices, bank statements, logbooks, and payroll records for six years from the end of the last tax year they relate to. Digital copies are fine, so the modern answer is simple: snap or forward every receipt into your accounting system the day you get it.

The burden of proof runs in one direction. If the CRA questions a deduction and you cannot produce the record, the deduction is usually denied, and the reassessment comes with interest. A credit card statement alone often is not enough; the CRA wants the actual receipt showing what was purchased.

Why do most businesses miss deductions?

Not because the rules are secret. Because the expenses never make it into the books. The subscription billed to a personal card. The cash parking fee at a client site. The home internet nobody prorated. Six untracked expenses a month at $50 each is $3,600 a year of vanished deductions.

This is the unglamorous truth of tax season: deductions are captured in the bookkeeping, not the tax return. By the time your accountant prepares the T2 in the spring, they can only work with what was recorded. Clean monthly bookkeeping also keeps your HST input tax credits flowing, since every missed receipt loses you the 13% twice: once as a deduction, once as a credit.

If you suspect your books are leaking deductions, a free assessment takes about five minutes and will show you where.