An assistant connected to your books can pull every figure a GST/HST return needs, check those figures against the ledger they came from, and hand you a line-by-line list ready to key in. It cannot file. The return goes into the Canada Revenue Agency's systems, and closing the period happens in QuickBooks Online. What you get back is the half hour of checking that normally does not happen. That is where the errors live.
How to file a GST/HST return online
As of September 2026, almost every registrant has to file electronically. The CRA lists six ways to file: in your CRA account (My Business Account or Represent a Client), through the online GST/HST NETFILE form, through a participating financial institution using Electronic Data Interchange, by uploading a file produced by third-party accounting software, by phone through GST/HST TELEFILE, or on paper by mail. Mail now carries a penalty unless you are a charity, a selected listed financial institution, or you hold an exemption granted case by case. Filing inside your CRA account is the only route that needs no four-digit access code and still lets you include schedules, elections and rebates. Whichever route you take, the numbers come from your books: total revenue on line 101, tax collected on line 103, input tax credits on line 106, net tax on line 109.
When the return is due
Your due date follows your reporting period, and both are visible in your CRA account. Monthly and quarterly filers have one month after the end of the period: a period ending 31 July is due 31 August. Most annual filers have three months after their fiscal year end. The exception worth knowing is the sole proprietor with a 31 December year end and business income for tax purposes, who pays by 30 April but does not have to file until 15 June. If the due date lands on a weekend or a CRA-recognized holiday, the next business day counts as on time.
You file for every period even when nothing happened. No transactions, no net tax, or an account you are closing: it is still a return, filed as a nil return.
What the working copy is for
The CRA publishes a printer-friendly working copy of the return as a PDF. It is a worksheet, not a filing: you use it to calculate net tax and hold the numbers while you key them into whichever service you file with, and the CRA asks you not to mail it. That worksheet is exactly the artifact an assistant is good at filling. There is no login and no submit button, so a wrong line on the first pass costs nothing.
The lines that matter for most small companies are short. Line 101 is total revenue for the period, excluding GST, HST and any provincial sales tax. Line 103 is the tax you collected or were required to collect, on paid and unpaid invoices alike. Line 104 holds adjustments that increase net tax, and 105 is 103 plus 104. Line 106 is your eligible input tax credits, 107 is adjustments that decrease net tax, and 108 is 106 plus 107. Line 109 is 105 minus 108, and that is your net tax. In an electronic return, 105, 108 and 109 calculate themselves.
Prepare the return in QuickBooks Online
QuickBooks does the arithmetic and tracks the deadline, then stops. Per Intuit's Canadian help article, filing is four steps: prepare the return in QuickBooks Online, submit it to the CRA, close the filing period in QuickBooks, and record the payment or refund.
To prepare it, go to All apps, select Sales Tax, then Overview, find the tax agency, and on the Filings tab select Prepare return beside the return that is due. Check the start and end dates, which QuickBooks fills from the CRA payment schedule. Review each line, select a dollar amount to see the transactions behind it, and use Adjust for a correction. The GST/HST Summary report gives you the same line-by-line breakdown outside the filing screen, the Sales Tax Liability report covers what you owe for the period, and the Exception Detail report shows transactions that will land on your next filing because they were dated into a period already closed.
Two things to be clear about. QuickBooks Online stopped supporting e-filing of sales tax on 21 April 2020, so the actual submission happens on the CRA's website either way. And Mark as filed closes the period in your books: once you do it, transactions in that period can no longer be added or edited, and QuickBooks posts a journal entry for the amount owing. Do the checking before you press it, not after.
The check to run before you file
Every question below runs on a read-only connection, which is what every Caribooks company starts with. Ask them in one conversation so the answers stay in context.
| Step | Ask | What you are looking for |
|---|---|---|
| The numbers | "Tax summary for 1 July to 30 September 2026." | The figures that go on lines 101, 103 and 106 |
| The counter-check | "Balance sheet as of 30 September 2026. What is the GST/HST payable balance?" | It agreeing with net tax for the period |
| Coding gaps | "Pull every purchase and bill in the quarter and list the ones with no tax code." | Expenses whose ITCs you are silently not claiming |
| Odd codes | "Which invoices this quarter used a tax code other than our usual one, and why?" | Zero-rated or exempt sales coded by accident |
| Evidence | "Which expenses in the quarter have no attachment?" | ITCs you cannot support if asked |
| Cut-off | "Anything dated in the quarter that was entered after 30 September?" | Late entries that belong on this return |
None of this is difficult. It is tedious enough that in a normal quarter nobody does it, and the mistake survives until year end.
Does the tax summary agree with the balance sheet?
This is the one check worth doing every single period, and it is two calls: get_tax_summary for the period, get_balance_sheet as of the last day of it. Net tax on the summary and the movement in the GST/HST payable account should tell the same story. When they do not, Intuit's own guidance points at the usual culprit: a journal entry posted straight to the sales tax payable account with no tax code on the line. Those entries move the account balance and never appear in the Sales Tax centre, so the two numbers drift apart and the return quietly stops matching the ledger.
An assistant is good at this because it can hold both reports at once and say where the difference came from. It is not good at deciding what to do about it. A journal entry to a tax account is usually somebody's deliberate correction, and reversing it because it looks untidy is how you file a wrong return confidently.
Input tax credits with no receipt behind them
You can claim an ITC for the GST/HST paid on property and services acquired for your commercial activities. You cannot claim one for a personal expense, or for purchases made to produce exempt supplies. That is the CRA's own list of common mistakes, and it is a coding question before it is a tax question: an expense in the wrong account with the wrong tax code is an ITC error waiting to be found.
find_expenses_without_attachments does the other half in one call. It compares every purchase and bill against every attachment in the file and returns what has nothing behind it, newest first. Read it as a list of ITCs you would struggle to support, not as a list of errors. The guide on categorizing a month of expenses covers the coding side in more detail.
Line by line, into the working copy
Example output, on a fictional company. Studio Nord is a six-person design studio registered in Ontario, quarterly filer, calendar fiscal year.
"Tax summary for 1 July to 30 September 2026, laid out as the lines of the GST/HST return, and tell me whether it agrees with the balance sheet."
| Line | What it is | Amount |
|---|---|---|
| 101 | Total sales and other revenue | 187,400 |
| 103 | GST/HST collected or collectible | 24,362 |
| 105 | Total GST/HST and adjustments | 24,362 |
| 106 | Input tax credits | 6,180 |
| 108 | Total ITCs and adjustments | 6,180 |
| 109 | Net tax | 18,182 |
Three things to look at before filing:
- GST/HST Payable on the balance sheet at 30 September is 18,362, which is 180 more than line 109. One journal entry on 12 August credits the account for 180 with no tax code on the line, so it never reached the tax summary.
- Four purchases totalling 3,410 before tax carry no tax code. If they are taxable, about 443 of ITCs is missing from line 106.
- Nine expenses in the quarter have no attachment, covering 412 of the ITCs claimed.
That is a return you can key in, plus three questions with names and dates attached. Whether the 180 journal entry is a correction to keep or an error to reverse is yours to answer, and if you are not sure, it is your accountant's.
If you are on the quick method
The quick method replaces most ITC tracking with a flat remittance rate applied to your GST/HST-included revenue. You still charge tax normally, you still file the same return, but line 103 becomes line 101 multiplied by your remittance rate, plus tax on any supplies not eligible for the calculation. You cannot claim ITCs on operating expenses, only on things like land and property you would claim capital cost allowance on. If your election was in effect at the start of the fiscal year, you also get a 1 percent credit on the first $30,000 of eligible supplies, entered on line 107.
Eligibility is a $400,000 test: worldwide taxable supplies including GST/HST, yours and your associates', over four consecutive fiscal quarters within your last five. Whole categories are shut out, including bookkeeping, tax and financial consulting, legal, accounting and actuarial services. So the accountant reading this cannot elect it, and neither can their bookkeeper.
An assistant can tell you what the last four quarters of revenue were and what each method would have cost you. It should not make the election. That is Form GST74, it binds you for at least a year, and whether it beats the regular method depends on facts about your purchasing that no report shows.
Where this is the wrong tool
You are in Québec. Revenu Québec generally administers the GST/HST there, and a business physically located in Québec files with Revenu Québec on its forms, not with the CRA. The French version of this guide covers the combined GST/QST return.
Your place-of-supply position is unclear. Selling across provinces, to non-residents, or digitally changes which rate applies and sometimes whether tax applies at all. A report tells you what was coded. It does not tell you what should have been.
Anything with a penalty attached. Late filings, voluntary disclosures, an assessment you disagree with, a return you need to amend. These have deadlines and consequences, and they belong with a professional who can be responsible for the answer.
Your books are not reconciled. Running any of this on a quarter where the bank feed is not accepted through the last day produces a tidy return built on unfinished numbers.
If nothing is connected yet, start with connecting QuickBooks to Claude. Everything above runs on read-only access, so a full pre-filing check costs you nothing but the reading. Canadian companies are supported the same as US ones, which is worth saying because Intuit's own connector is not available in Canada. More on how the connector works is on the QuickBooks MCP page.