This is general information, not professional tax advice. For official guidance, see the CRA's page on telephone and utilities expenses (Line 9220) or talk to a tax professional.

If you're self-employed and your phone is basically an extension of your business — texting clients, checking email, taking calls — you've probably wondered whether you can write off some of that monthly bill. The short answer is yes, but "some" is doing a lot of work in that sentence.

The short answer

You can deduct the portion of your cell phone bill that reasonably relates to earning your self-employment income. There's no CRA-published fixed percentage — no "50% for everyone" rule like there is for meals. You work out a reasonable business-use percentage yourself, apply it consistently, and keep records that back it up.

Personal vs. business use

CRA's position on business-use percentage

The CRA's own guidance on Line 9220 (telephone and utilities) says you can deduct the percentage of airtime expenses for a cell phone you use to earn your business income. That's deliberately open-ended: the CRA is trusting you to land on a number that reflects reality, not to just pick 100% because the phone is convenient.

If you bought the phone itself, note that the purchase price isn't a straight write-off either — it falls under capital cost allowance (CCA) rules, along with any interest on financing, prorated by the same business-use percentage.

How much can you actually claim?

There's no single right method, but common, defensible approaches include:

  • Call/text/data log review — for a representative month or two, count what fraction of your usage was client calls, business texts, or work email versus personal.
  • Time-based estimate — if you use the phone for work roughly 3 days out of a 7-day week of "phone activity," 40-50% might be defensible — but this needs to reflect your actual pattern, not just sound reasonable.
  • Separate line or device — if you have a phone or plan used exclusively for business, that changes the math substantially in your favour, since the airtime is 100% business.

Whatever percentage you land on, the important thing is that you could explain and defend it if asked — "I just guessed" doesn't hold up well in a review.

Internet bill: same rules?

The same underlying principle — deduct only the business-use portion of a mixed-use expense — applies to internet service. There isn't a separate CRA line item spelling out a specific internet formula the way there is for cell phones; instead, apportion it like any other reasonable current expense used partly for business. If you also claim a home office, your internet may instead (or additionally) factor into your business-use-of-home calculation on Line 9945 rather than as a standalone utility — don't double-count the same expense in two places.

What about home phone?

This one trips people up. The CRA is explicit here: you cannot deduct the basic monthly rate of your home landline, even if you use it for business calls sometimes. Two exceptions:

  • Long-distance calls made on your home phone for business purposes are deductible.
  • If you have a second phone line at home used only for business, its basic monthly rate is deductible in full.

In practice, most freelancers today don't have a landline at all, which is part of why the cell phone question comes up so much more often.

How to prove business use to the CRA

You don't need to submit a log with your tax return, but if the CRA asks questions later, you want to be able to show your work:

  • How you arrived at your percentage (a sample month of itemized usage is the gold standard).
  • That you applied the same percentage consistently through the year, and reassessed it if your work patterns changed materially.
  • The actual bills showing the total amount paid, so the dollar math is traceable.

Keeping records: invoices and usage logs

Keep the monthly bill (PDF or paper) for every month you're claiming, plus whatever you used to calculate your business-use percentage — screenshots of a usage breakdown, a short log, or notes on how you estimated it. Under the CRA's general record-keeping rule, hang onto these for six years from the end of the relevant tax year, the same as any other receipt.

That's also exactly the kind of paperwork that's easy to lose track of one bill at a time and painful to reconstruct in April.

Phone and internet bills pile up fast. SnapReceipt reads PDF phone bills automatically — Bell, Rogers, and Telus bills even get split into one line item per phone number — and categorizes each one so your business-use expenses are organized in your own Google Sheet all year, not reconstructed from memory in tax season. It's free during beta, no credit card required.

This is general information, not professional tax advice. Always confirm current rules on canada.ca or with a qualified tax professional.