If you run your business from home — even part of the time — the Canada Revenue Agency (CRA) allows you to deduct a portion of your home expenses. It's one of the most valuable deductions available to Canadian small business owners, yet it's also one of the most commonly miscalculated.

Here's what you need to know to claim it correctly.

Who Can Claim Home Office Expenses?

To deduct home office expenses, your workspace must meet at least one of these CRA conditions:

• It is your principal place of business — meaning you do most of your work there
• You use it exclusively and regularly to meet clients, customers, or patients

If you work from home full-time or use a dedicated room for client meetings, you almost certainly qualify. If you occasionally answer emails from your kitchen table, you likely do not.

What Expenses Are Deductible?

The CRA allows you to deduct a proportional share of the following home expenses:

For Renters

• Rent
• Heat and electricity
• Water
• Internet (business portion — see below)
• Home insurance
• Maintenance and minor repairs

For Homeowners

• Heat and electricity
• Water
• Home insurance
• Maintenance and minor repairs
• Property taxes
• Mortgage interest (not principal)

Note that homeowners cannot deduct capital cost allowance (CCA) on their home — doing so can trigger capital gains tax when you sell, which typically outweighs the benefit.

How to Calculate Your Workspace Percentage

The CRA accepts two common methods:

1. Square footage method Divide the square footage of your workspace by the total square footage of your home.

Example: Your home office is 150 sq ft. Your home is 1,500 sq ft. Your workspace percentage is 10%.

2. Number of rooms method Divide the number of rooms used for business by the total number of rooms in your home (excluding bathrooms).

Example: You use 1 room out of 8 rooms in your home. Your workspace percentage is 12.5%.

Use whichever method gives you the most accurate reflection of your actual business use — and apply it consistently year over year.

The Internet Expense: A Special Case

Internet is deductible, but only the business-use portion. If you use your home internet for both personal and business purposes, you need to estimate a reasonable split.

A common approach is to track how many hours per day the connection is used for business versus personal use, then apply that ratio to your monthly bill. Keep a log if CRA ever asks.

What About the T2200 and T777?

If you are an employee working from home (rather than a self-employed business owner), the rules are different. You would need a signed T2200 from your employer and would file a T777 to claim employment expenses.

Self-employed individuals and incorporated business owners report home office expenses differently:

• Sole proprietors claim home office expenses on Form T2125 (Statement of Business Activities)
• Incorporated businesses can reimburse the owner-employee for home office costs, but this requires a formal T2200 and careful documentation

If you operate through a corporation, speak with your bookkeeper or accountant before claiming — the optimal structure depends on your specific situation.

What You Cannot Deduct

The CRA is clear about what does not qualify:

• Mortgage principal payments — only the interest portion is eligible
• Capital improvements (renovations, additions) — these may be depreciable assets, not current expenses
• Expenses that exceed your net business income — home office expenses cannot create or increase a business loss (though they can be carried forward)
• Rooms used for both personal and business purposes — unless the business use is exclusive and regular

Documentation CRA Expects

If you are ever audited, CRA will want to see:

• Receipts or statements for all claimed expenses (rent, utilities, insurance, etc.)
• A floor plan or sketch showing the dimensions of your workspace and the total home
• Evidence that the space is used regularly and exclusively for business (photos help)
• Your calculation method and the percentage applied

Keep these records for at least six years from the end of the tax year they relate to.

A Practical Example

Sarah runs a bookkeeping practice from a dedicated home office in Toronto. Her home is 1,200 sq ft and her office is 120 sq ft — a 10% workspace ratio.

Her annual home expenses:

• Rent: $24,000
• Utilities: $2,400
• Internet (business portion, 60%): $720
• Home insurance: $1,200

Total home expenses: $28,320 Deductible amount (10%): $2,832 + $720 internet = $3,552

That's over $3,500 in legitimate deductions Sarah would miss if she didn't track her home office properly.

Keep It Clean, Keep It Consistent

The home office deduction is legitimate and valuable — but it attracts CRA scrutiny when it looks inflated or inconsistent. The best approach is to:

1. Choose a calculation method and stick with it
2. Keep all receipts and utility statements organized
3. Document your workspace with photos at year-end
4. Review your percentage annually if your home or office size changes

If you're unsure whether your home office qualifies or how to calculate it correctly, a professional bookkeeper can review your setup and make sure you're claiming everything you're entitled to — without the risk of an audit flag.

My Book Solutions works with Canadian small business owners, medical clinics, law firms, and non-profits to keep their books accurate and their tax deductions optimized. Reach out to learn how we can help.