First off I'm very new to this so some of my questions may be silly. I worked for several companies that issued me a T4A which means I need to fill out a T2125 with business expenses. To my understanding I can claim the portion of my cellphone bill related to work. I hadn't been keeping track of it and was wondering how can I estimate which portion was used for work, and in the event of an audit how would such a thing be proven?

What parts of using a smartphone even count?

Here is a hypothetical example to show what I mean: On an average week: 5 hours spent on work related phone calls 5 hours spent on personal phone calls. So from this would I claim 50% of the bill? What if I then spent 5 hours a week playing a game on my phone, then would the claim be 33.3%?

What about how I need Google Maps for work, or the phone's camera? How would I count the time reading text messages and emails on my phone?

  • In my case, I can use my phone for work a lot and it doesn't cost me anything (unlimited texts, unlimited calls, plenty of data leftover every month). What now? If it cost me money I wouldn't use it for work, but it doesn't.
    – gnasher729
    Commented Nov 17, 2018 at 22:09

1 Answer 1


I'll give you the practical answer my tax advisor gave me.

First off, it's not about how much you use your phone, its about what fractionof the charges are work related.

Second, as long as your claim is reasonable and the amounts are small, the CRA doesn't care about them being precisely accurate.

Guess how much you use your phone for work, then claim that. If you want slightly more accuracy go through one months charges and work out what proportion were work related, then claim that proportion of all the charges.

EDIT I'm suggesting approximating the year bill by figuring out what proportion of the charges for a single month are work, then applying that proportion across the year.

So say you pick you pick last month, go through it and you find that 43% of the charges for that month are work related. Then claim 43% of the year's charges as work related. As long as you didn't deliberately pick a month with very high or very low work charges CRA will almost certainly be fine with it. Tell the CRA that's what you've done on the form.

  • This is per year right? So I should add up all my cellphone bills for the year and then figure out the portion that is work related?
    – Latchar3
    Commented Nov 23, 2018 at 20:30
  • That's a lot of work. I added an edit to make what i'm suggesting clearer. Commented Nov 23, 2018 at 22:00
  • Perfect, except last month may be dump - see, last month is December which normnally has christmas holidays. Many people take a whole week off then. Same in Janaury. I would take a month that has zero holidays ;)
    – TomTom
    Commented Nov 24, 2018 at 9:21
  • That's probably a good policy. Commented Nov 25, 2018 at 23:32

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