How do I calculate the percentage of my home I can claim as a home office?
The standard CRA-accepted method is to divide the square footage of your dedicated workspace by the total square footage of your home. If your home is 1,500 square feet and your office is 150 square feet, your home office percentage is 10%. That fraction is then applied to eligible home expenses to determine your deductible amount.
There is flexibility in the method: the CRA also accepts a room-count method (number of rooms used for business divided by total rooms), which may produce a higher percentage for some homes. Use the method that most accurately reflects actual business use, and apply it consistently from year to year.
Important: the workspace must be used exclusively or primarily for business during business hours. A spare bedroom used as a home office but also as a guest room may not meet the exclusivity test, potentially disqualifying or reducing the deduction. Setting up a dedicated, consistently business-only space produces the strongest claim. If your workspace area changes during the year (for example, you move to a larger office within the home), you can prorate accordingly.
Key takeaways
- The common method is office square footage divided by total home square footage.
- A room-count method is also acceptable and may yield a higher percentage for some homes.
- Apply whichever method most accurately reflects business use and use it consistently.
- The workspace must be exclusively or primarily business-use — dual-purpose rooms may not qualify.