If you're self-employed and work from home, you likely qualify for the business-use-of-home deduction, but the amount you can claim depends on square footage, not vibes. If you're an employee working from home for your employer, the rules are stricter and you need a signed form before you claim anything. Start by figuring out which category you're in, because the CRA treats them differently.
Are you self-employed or an employee working from home?
This is the first fork in the road. Self-employed people (sole proprietors, freelancers, most contractors) claim home office costs on Form T2125 as part of their tax return. Employees need a T2200 or T2200S signed by their employer confirming the work-from-home arrangement before they can claim anything on Form T777.
A lot of people assume working from home a few days a week is enough. It isn't, on its own. The test is about why and how often you use the space, not just that you happen to log in from your kitchen table some mornings.
The two tests CRA uses for self-employed claims
For sole proprietors, the CRA (under the Income Tax Act) allows the deduction if one of two conditions is met:
- Principal place of business. The space is where you mainly run your business, more than 50% of the time.
- Regular and exclusive client meeting space. You use the space only to earn business income, and you meet clients, customers or patients there regularly, even if it's not your main workspace.
Most home-based consultants, bookkeepers, designers and tradespeople who do their invoicing and admin from a spare room meet the first test easily. A dedicated room used only for work is cleaner to defend than a desk in the corner of a shared living room, though CRA doesn't require a separate room by law, just that the use is real and ongoing.
How to calculate the deduction
The standard method is square footage. Measure the area you use for business and divide it by the total finished living area of your home. That percentage applies to your eligible home expenses for the year.
Eligible costs typically include:
- Utilities. Electricity, heat, water.
- Home insurance. The portion tied to your business-use percentage.
- Property tax. Again, prorated.
- Maintenance and minor repairs. Costs that benefit the whole home, like furnace servicing.
- Mortgage interest (for owners) or rent (for renters). Only the interest portion of a mortgage payment counts, never the principal.
Example: your home is 1,400 square feet, and your office is 140 square feet. That's 10%. If your total eligible home costs for the year are $18,000, your claim is $1,800, before any adjustment for a loss limit.
One real limit matters here: home office expenses can't create or increase a business loss. If your business income before the home office deduction is $1,200, you can only claim up to $1,200 this year. The unused portion isn't lost, it carries forward to apply against the same business next year.
What you can't claim and common mistakes
Mortgage principal payments are never deductible, only the interest. Capital cost allowance on your home is technically possible but rarely worth it, because claiming it can affect your principal residence exemption when you sell. Most accountants, including us, advise against it for a modest home office claim.
Another common mistake: claiming 100% of internet or phone bills when the plan is also used personally. CRA expects a reasonable business-use percentage there too, estimated and documented, not guessed at tax time.
Keep your utility bills, mortgage interest statement or lease, property tax bill, and a simple floor plan with measurements. If CRA ever asks questions, that's the file you want ready. This is also where good year-round bookkeeping pays off, rather than reconstructing square footage and bills in April.
Employees working from home: different rules apply
If you're a T4 employee, the temporary flat-rate method that many people used during 2020 to 2022 is no longer available. For current tax years, employees need the detailed method: a T2200 or T2200S signed by the employer, and Form T777 calculating actual expenses using the same square footage logic described above, applied to a narrower list of eligible costs (rent, utilities, minor supplies, and in some cases a portion of home insurance and maintenance, but not property tax or mortgage interest for most employees). Confirm the current year's eligible expense list on the CRA website before filing, because this is an area that changes.
GST/PST and your home office
If you're a GST/HST-registered sole proprietor, you can generally claim input tax credits on the business-use portion of expenses that included GST, like utilities in some cases or a portion of a new home internet plan. BC's PST doesn't apply the same way to most home utility costs, so the main benefit here is on the GST/HST side. This is a detail that's easy to miss if your bookkeeping system isn't tracking business-use percentage consistently through the year.
If your home office claim involves a mortgage, a mixed-use space, or you're not sure whether you meet the principal-place-of-business test, it's worth having a bookkeeper or accountant review it before you file rather than after CRA asks questions. Have your square footage, a full year of utility and insurance statements, and your mortgage or lease details ready. Reach out to Sarv Accounting Services and we'll walk through your specific setup and calculate the claim properly.
Frequently asked questions
Can I claim a home office if I only work from home part-time?
Yes, if the space is still used regularly and meets one of the two CRA tests: it's your main place of business, or you use it exclusively and regularly to meet clients. Occasional use a day or two a week, mixed with other workspaces, is harder to justify as a deduction.
Does renting versus owning change how I calculate the deduction?
Not the method, just the inputs. Renters prorate their rent by business-use percentage, while owners prorate mortgage interest, property tax, and home insurance the same way. The square footage calculation stays the same either way.
What happens if my home office deduction is more than my business income?
You can only deduct up to the amount of your net business income for the year, so the claim can't create a loss. Any unused portion carries forward and can be applied against that same business's income in future years.