What is the business-use-of-home deduction?

Business-use-of-home is a means by which a business owner can deduct expenses for the business use of a work space in your home, as long as you meet one of the following conditions:

  • it is your principal place of business; OR
  • you use the space only to earn your business income, and you use it on a regular and ongoing basis to meet your clients, customers, or patients

You can deduct part of your maintenance costs such as heat, home insurance, electricity, and cleaning materials. You can also deduct part of your property taxes, and mortgage interest.

How do you calculate business-use-of-home?

The allowable business-use-of-home expense is calculated in three steps:

  • Total up all allowable expenses that comprise the cost of maintaining a home;
  • Multiply that subtotal by a percentage representing the business portion of the home; and
  • Compare with existing income and expenses to determine how much of this expense can then be applied as a business expense.

Pro-rating Business-use-of-home Expenses

CRA requires that a reasonable percentage be used to calculate how much of the total home costs may be used as a business deduction. The percentage must be based on the business vs personal use of space in the home.

The amount of space used for business-use-of-home can be either based on the area taken up by the home office as a percentage of the total area of the home, or by the number of rooms taken up by the business as a percentage of the total rooms in the house.


Justin works out of a spare bedroom in his home. The room makes up 15% of his total home. The home has a total of five rooms, and the office takes up the entire spare bedroom.

Justin can use either 15% (based on area) or 20% [1 room out of 5 = 20%] as his percentage of business use.

Time of use comes into play if the business portion of the home reverts to personal use for part of the day or year. E.g., if the business is run from the dining room table but the room is still used as a dining room outside business hours, the business-use-of-home claim must be prorated to take into account the fact that the dining room is only devoted to business use for part of the day.

Similarly, if the business is only run for part of the year, the business-use-of-home claim also needs to be adjusted to take this into account.


Tara begins running her business from her home office on July 1 and continues to the end of the year. The business-use-of-home space takes up 20% of her apartment. Her total housing costs in the year come to $24,000.

Tara can claim $2,400 for business-use-of-home: $24,000 x 20% of the space x 50% of the year.

Types of Business-Use-Of-Home Expenses

The following expenses can be included in the initial calculation of the cost of maintain the home:

Rent (for business-use-of-home)

If the home is rented, include the rent. Note that there is a ‘Rent’ expense line on T2125 that is never used for home offices. The Rent expense on line 8910 of T2125 is only for business-only spaces that are rented outside the home.

Mortgage interest (But not principal)

Note that only the interest portion of the mortgage payment can be treated as an expense. The principal is not included, mainly because it is not considered an expense: paying the principal of your mortgage is like converting one asset (cash) into another (home equity).

Utilities (business-use-of-home only)

Utilities can include heat, electricity and water.

Security Systems

Include any monitoring fees for security systems.

Property tax

Like rent, this should include the full amount of property tax you spend on the residential home in which you have your office; this amount should not be included on line 9180 of the T2125.

Cleaning services

If you hire a cleaner, their services are considered part of maintaining your home. Be sure to obtain receipts or pay via the bank (i.e., by cheque, email transfer, or other form of payment that is handled directly by your bank) so that you can provide proof of payment if the government requests to see it.

Repairs (But not renovations)

A repair is a change to the home that returns it to its original (to you) condition. A renovation is a change that improves it beyond that point.

Repairs to the home in general can be included in the business-use-of-home calculation. It may seem counterintuitive that, say, a plumbing repair is included when calculating the business-use-of-home expense of a home office that doesn’t itself contain any plumbing, but nevertheless it’s allowable.

Renovations, on the other hand, cannot be used as business expenses. A renovation is defined as a change that increases the value of the home by bringing it to a better state than it was in when it was purchased. The exception to the ‘no renovations’ rule is expenses you incur for eligible disability-related modifications made to a building in the year. These can be deducted as expenses as part of business-use-of-home.


Sharon runs her business from her home office throughout the year. The home office takes up 25% of her apartment and is used exclusively for her business.

Her housing costs for the year are as follows:

Rent: $12,000

Electricity: $400

Total: $12,400

Her allowable business-use-of-home deduction is $3,100 [25% of $12,400]

Note: the preceding discussion refers only to business-use-of-home deductions from self-employment income. A form of business-use-of-home deduction is also available to some employees under certain circumstances as an employment expense (in situations where an employee receives a T2200 Conditions of Employment form from their employer). However those kinds of business-use-of-home expenses are subject to different rules. Refer to CRA’s guidance regarding T777 Employment Expenses.