The help pages cited here were read on October 26, 2026. We describe the paths as those pages describe them: the exact interface labels may differ from one account to another, and we did not redo the path inside an ad account for this post. Nothing below is tax advice: Google and Meta both write that they cannot give any, and the same reservation applies here.

What the two platforms add when the number is missing

At Google, the "Taxes in your country" page writes for Canada that GST/HST applies to all Google Ads customers with a billing address in Canada who have not added a registration number to their payments profile. For Québec, it adds that the Québec Sales Tax rate is 9.975% and applies to all Google Ads customers in the province who haven't added a QST registration number to their payments profile. To find the GST/HST rate of a province, the page points to the local tax authority.

At Meta, two help pages complement each other. Beginning July 2021, Meta ads in Canada are subject to GST or HST at the applicable local rate: this applies to advertisers whose "Sold to" country on their business or personal address is set to Canada and who haven't added their GST/HST number to their ad account. Beginning March 2019, Meta ads in Québec ("Facebook ads" in the French-language version of the page) are subject to QST at the applicable local rate: this applies to advertisers whose "Sold To" province on their business or personal address is set to Québec and who haven't added their QST registration number to their ad account.

Both platforms therefore add taxes to ad purchases when the numbers are missing from the payment profile. The effect reads in one line. Revenu Québec describes the calculation at the till: GST at 5% and then QST at 9.975% applied to the same selling price, or 14.975% in a single step. If the same reasoning holds on an advertising invoice, which the help pages do not specify, a media budget of $10,000 before tax would see $1,497.50 added. The exact amount is read on the invoice, not in this calculation.

Google Ads: where to enter the numbers

The help page distinguishes two situations.

Postpay or prepay. The advertiser updates the tax information themselves. In the Google Ads account, they click the Billing icon, then Settings. Under "Payer details", they locate "Canada tax info" and click "Manage tax info". On the next page, "Add tax info", then enter the number in the optional tax registration number field, and "Submit". The same operation exists in the Google payments center: Settings, "Canada Tax Info", the pencil icon, "Manage tax info", "Add tax info", then "Save". For QST, the page says to provide the registration number following the same instructions.

Monthly invoicing. Advertisers on monthly invoicing must contact Google's support team and provide their GST/HST registration number, and their QST registration number for Québec, so its specialists update the payments profile. The page reserves the update from the account for advertisers on postpay or prepay.

The Canada section of the page does not say whether adding the number corrects invoices already issued, and it promises nothing on timing. The only reliable check is therefore the next invoice: the tax lines appear on it or no longer do.

Meta: where to enter the numbers

Meta writes that, in the Payment settings, the advertiser can add their GST/HST number to their account so it shows on their ads receipts, and that if they do, Meta doesn't add GST/HST to their purchases of ads. For Québec, the QST page specifies that the QST number and the GST/HST number can be added so they appear on receipts. If both numbers are added, Meta adds neither GST/HST nor QST; if the advertiser does not add both, Meta adds both taxes, and the page does not address the case of a single number being entered.

Two further points on the same page change how the amounts read. The taxes are charged whenever the ads are billed, whether the ads are for business or personal purposes. And because they are added on top of charges, they don't make the billing threshold arrive sooner, but the total of an invoice can exceed the threshold amount. When ads are paid with funds added to the account ("manual payment method" on the GST/HST page, "available funds" on the QST page), the tax is calculated at the applicable rate when those funds are added.

Meta also points, for advertisers accepted by its local sales team and on monthly invoicing, to separate pages. We have not read them: an account on monthly invoicing at Meta should consult them rather than what precedes.

The digital services tax: what was charged, what is credited

Google's payments center summarizes the timeline in its Canada digital services tax (DST) FAQ. Google ceased charging the fee effective July 1, 2025, after the Canadian Department of Finance announced on June 29, 2025 a commitment to rescind the legislation. Bill C-15 received Royal Assent on March 26, 2026, and the Digital Services Tax Act is now repealed. Google states that it has started crediting the fees charged: the credits cover the Canada DST fees charged between October 1, 2024 and June 30, 2025, across Google Ads, YouTube Reservation and Display & Video 360. The page on surcharges for specific jurisdictions specifies that, as of July 1, 2025, ads served in Canada are no longer subject to the 2.5% DST fee.

The form of the credit depends on the billing type, again according to Google's FAQ.

  • Google Ads on direct terms, prepay or threshold: an account-level credit adjustment, which automatically reduces the outstanding balance or increases the prepaid balance. No action is required.
  • Agencies, resellers and Display & Video 360 customers: an account-level credit memo, to be applied to open invoices in the Google payments center. Applied by the customer themselves, it takes effect immediately; if Google's team has to apply it manually to specific past invoices, the FAQ announces 4 to 12 weeks.
  • The credit is granted even if the invoices containing the DST fees have already been paid, and no application or paperwork is needed. For a closed account that stays inactive with no contact with Google, the FAQ states that unclaimed balances may eventually be remitted to the relevant government authority, and that cash refunds exist for inactive accounts, with much longer wait times.

For an advertiser whose accounts are managed by an agency, the reading that follows from those rules, in our view, is to ask the agency whether it received a credit memo and to which invoice it applied it. That point is an accounting matter between the agency and its client: Google's FAQ does not cover it.

A ten-minute check

  1. Open a recent Google Ads invoice and a Meta one, and find the GST/HST and QST lines.
  2. If the lines are present while the business is registered for GST/HST and QST, open each platform's payment settings and check that the numbers are entered.
  3. At Google on monthly invoicing, write to support with both numbers rather than looking for the field in the account.
  4. At Meta, check that the country and province of sale on the address match the business's actual address: the tax follows those fields.
  5. For Google invoices from October 1, 2024 to June 30, 2025, check for a DST line and, if there is one, for a credit adjustment or credit memo in the payments center.
  6. Note the date of each check and the result on the next invoice.

What these numbers do not settle

Adding a number to a payment profile changes what the platform adds to the invoice. Whether the business must be registered, and how it recovers the taxes paid on its purchases, is a matter for its accountant and Revenu Québec, not for an advertising help page. The same separation holds for sales: the rules on the price shown to the store's customers are in All-inclusive pricing in Quebec ads (s. 224.1) and, for the Merchant Center feed, in Merchant Center Canada: submit prices excluding tax. The overall framework is on our page advertising compliance in Québec and Canada, and our work on account setup is described on the page Google Ads in Montréal.