The Canada Revenue Agency (CRA) allows self-employed Canadians to write-off expenses reasonably incurred while pursuing profit for your business.
This includes expenses such as phones, internet and utilities. To write off your cell phone as a business expense, note your costs on Form T2125, Statement of Business and Professional Activities. This form helps you calculate your net business income.
If you use your cell phone for both personal and business use, you can only claim a portion of its cost as a business expense, recently, where a detailed log of personal vs business calls was not provided to the CRA, they denied the expense related to the calls, but allowed the cost related to the data. While this does not, and will not apply to everyone in all circumstances and situations, it is very important to have detailed records available.
For example, if you use it equally for personal and business use, you can write off half of your bill as a business expense.
If you buy a cell phone, you may not be able to write off the full cost the year of purchase. Instead, you may need to determine its Capital Cost Allowance and claim its cost over a number of years.