How to file a GST/HST return: a line-by-line workflow for Canadian bookkeepers

Canada’s sales tax is harder to code than to file. The return has a handful of lines and the CRA’s software adds them up for you. The difficulty sits upstream: rates that change with the province, provincial sales taxes that are not recoverable sitting on the same invoices as GST that is, and documentation rules that change with the size of the purchase. By the time a bookkeeper opens the return, the result has already been decided by how each transaction was coded. This guide follows one filing run from closing the period to paying, then covers what to do about missed credits, errors, and late returns. The rules behind the codes are in the Canadian GST/HST guide. Every figure links to the CRA in the Sources section.

Step 1: close the reporting period

• Reconcile every bank and credit card account to the last day of the period.
• Enter all sales invoices and all purchases with supporting documents.
• Clear uncoded transactions.
• Confirm the reporting period and accounting method the client is registered for, including whether they use the Quick Method, which changes how the return is calculated.

Step 2: review the tax codes

Run the sales tax detail report and read it for exceptions.

• Province. The rate follows the place of supply, not the supplier’s head office. An Ontario rate on an Alberta purchase is the most common error in multi-province files.
• Recoverable against non-recoverable. GST and HST generate input tax credits. Provincial sales taxes in the provinces that levy them separately do not, and belong in the cost.
• Meals and entertainment, where only half the tax is claimable.
• Passenger vehicles and personal use.
• Zero-rated against exempt. Both show no tax, but exempt sales restrict the credits a business can claim.
• Imports and foreign suppliers, including digital services.
• Documentation. The information a receipt must carry to support a credit depends on the total: the CRA sets one level under $100, a second from $100 to $499.99, and a third at $500 or more ^[1] . A large purchase supported only by a card slip does not qualify.

Step 3: the lines

The CRA’s instructions name each line of the return ^[2] . When filing electronically, the totals are calculated for you.

For most small businesses the working lines are 101, 103, and 106. If there is no revenue to report, line 101 is zero ^[2] , and the return is still filed.

Step 4: test the numbers

• Line 103 against line 101. Divide one by the other. For a business selling only taxable goods in one province, the result should be that province’s rate. A lower figure needs explaining by zero-rated, exempt, or out-of-province sales.
• Line 101 against the income statement. Revenue for the period should agree, or you should be able to list the differences.
• Line 106 against purchases. Compare the ratio of credits to total purchases with the last few returns. A jump is a question.
• Net tax against the ledger. After the return is prepared, the GST/HST accounts should equal line 109 plus anything unpaid from earlier periods.
• Direction. A refund for a client who normally pays should have a one-sentence explanation, such as a large equipment purchase.

Step 5: file electronically

Electronic filing is no longer optional for most registrants. The CRA removed the mandatory electronic filing threshold for reporting periods beginning on or after January 1, 2024, so all GST/HST registrants, except charities and selected listed financial institutions, must file electronically. The penalty for not doing so is $100 for the first return and $250 for each subsequent return ^[3] .

The usual routes are GST/HST NETFILE, the client’s My Business Account, and accounting software that files directly. A bookkeeper acting for a client files through Represent a Client once the business has authorized them, either by adding the representative in My Business Account or by confirming the representative’s request there ^[4] . Set that up at onboarding; see the client onboarding checklist.

Get the client’s written approval of the figures before filing.

Step 6: pay by the deadline

These are the CRA’s deadlines ^[5] . For 2026, the last row means payment by April 30, 2026 and filing by June 15, 2026. Annual filers may also have quarterly instalments, due within one month after the end of each fiscal quarter ^[6] . All dates are in Canadian tax deadlines.

Missed credits and mistakes

A credit you did not claim. There is usually no need to amend. Most registrants can claim an input tax credit on a later return, provided it is filed by the due date of the return for the last reporting period that ends within four years after the end of the period in which the credit could first have been claimed. Certain large businesses and listed financial institutions have two years ^[1] . Pick the credit up on the next return and note which period it came from.

An error in what you reported. Amounts on a return already filed can be adjusted on request to the CRA, but the CRA’s policy is that it is not required to accept a request to amend and may refuse it in whole or in part ^[7] . In practice, under-reported tax should be corrected promptly, because interest runs from the original due date. Involve the client’s accountant where the amount is significant.

Keep a note of every correction with the working papers: the period, the amount, the cause, and where it was fixed.

If the return is late

The failure-to-file penalty has two parts: 1% of the net tax owing, plus 25% of that amount for each complete month the return is overdue, to a maximum of 12 months ^[8] . A person who fails to comply with a demand to file is liable to a further penalty of $250 ^[8] .

Because the penalty is a percentage of what is owed, a client who cannot pay should still file on time. Filing on time avoids the penalty and fixes the amount; the unpaid balance then carries interest.

After filing

• Lock the period in the ledger.
• File the working papers: the return as filed, the tax detail report, the reconciliation to the ledger, and the client’s approval. See workpapers and audit trail.
• At year end, agree the year’s returns to the sales tax accounts as part of the year-end checklist.

Where ExpenseFlow fits

The coding checked in Step 2 is set when each purchase is captured. ExpenseFlow reads every line of a bill or receipt and assigns a tax code that takes the province into account, and it flags province mismatches, missing or invalid tax codes, cross-border purchases coded as domestic, and documents where a valid tax invoice is required. Meals and entertainment that are only 50% claimable are split automatically into a claimable and a non-claimable line, each with the right tax code and account. It extracts the supplier’s GST/HST registration number from the document and shows it; it does not validate the number with the CRA. Each item waits in a review queue until a person approves it, then syncs to Xero or QuickBooks Online.

ExpenseFlow does not prepare or file the return and does not make payments to the CRA.