The calculation in plain terms
For each reporting period, start with the tax collected or collectible on your taxable supplies. Add any adjustments that increase the amount, then subtract your input tax credits and any adjustments that reduce it. The result is net tax.
The word collectible matters. Tax on an invoice generally belongs in the period of the invoice date, even if the customer has not paid yet. That is one reason cash balances rarely match the return.
Where it appears on the return
On the CRA’s return, line 105 is total GST/HST and adjustments, line 108 is total ITCs and adjustments, and line 109 is the difference: net tax. Line 110 is for instalments and other annual filer payments, and line 111 for rebates. A paper return then works through line 113 to either a refund claimed on line 114 or an amount owing on line 115.
Line numbers can differ by filing method, so use the current return rather than a remembered layout.
Two illustrative examples
In one period a business charges $1,300 of HST on $10,000 of sales and has $520 of input tax credits on its purchases. With no adjustments, net tax is $780, which is generally remitted.
In a heavy-spending period the same business charges $260 and has $650 of credits. Net tax is negative $390, so the return shows a refund claim. These figures are illustrative only.
Common mistakes and what to discuss
Typical problems include claiming credits without proper invoices, leaving out bad debt or credit note adjustments, treating collected tax as spending money, and forgetting that a return is required even with no activity. An annual filer whose net tax was $3,000 or more last year, and is expected to be $3,000 or more this year, generally has to pay quarterly instalments.
If you use the quick method, net tax is worked out with remittance rates instead of a full credit total. Bring sales reports, purchase invoices and last period’s return, and ask whether your reporting period still suits your volume.
Sources & editorial notes
Sources checked October 24, 2026. The examples are illustrative and provide general information. Discuss how the guidance applies to your circumstances with your accountant.
- General information for GST/HST registrantsCanada Revenue Agency
- Input tax creditsCanada Revenue Agency
Rules and guidance can change. Use the current official source and confirm the treatment for your facts. To flag an error, contact Sora.