Can you write off ChatGPT Plus for client proposals in Canada?

Yes — possibly, if ChatGPT Plus is used to earn business income in Canada. In general, the CRA allows you to deduct reasonable expenses incurred to earn business or professional income, so a subscription used for client proposals, drafting, research, or similar business work can often be claimed to the extent it is used for business.

Practical rule:

• Business-only use: you can generally claim the full subscription cost.
• Mixed personal and business use: claim only the business-use portion.

How Canadians usually claim it:

• Sole proprietors / freelancers: include it as a business expense on Form T2125, typically under Office Expenses (line 8810) or another appropriate miscellaneous expense category if that better fits your bookkeeping.
• Corporations: claim it as an operating expense on the corporate return.

Records to keep:

• Keep invoices and proof of payment.
• Keep a simple note showing how you determined the business-use percentage.
• Save the monthly PDF invoices from the billing portal, since those are useful support for your records.

GST/HST:

• Tax treatment can depend on the supplier setup, your province, and whether your business is GST/HST-registered.
• Verify the invoice and your account settings.
• If you are GST/HST-registered, you may be able to claim input tax credits where allowed.
• If you want to know whether tax was charged correctly or whether registration details should be added to your billing profile, check the official billing and CRA guidance or ask a CPA.

Bottom line:
If ChatGPT Plus is genuinely helping you produce client proposals or other business work, it is often a legitimate business expense in Canada — but only the business portion is normally deductible, and you should keep proper invoices and records.