QUARTERLY TAX PREP CHECKLIST: GST/QST TASKS EVERY 3 MONTHS

For many Quebec businesses, quarterly GST/QST filing is the default frequency. Every three months, you must summarize your taxable sales, calculate GST and QST collected, claim input tax credits, and remit the net tax owing to Revenue Québec. When the quarter ends, businesses often discover that their records are incomplete, receipts are missing, or POS reports do not match the accounting system. This leads to stress, filing delays, and a higher chance of errors or audits. A structured quarterly GST/QST checklist helps you prepare steadily during the period and close each quarter smoothly with an accurate, audit-ready return.

Quarterly tax preparation is not just about submitting the FPZ-500-V return. It is an opportunity to review your systems, clean up bookkeeping, and ensure that your business is collecting and remitting tax correctly. Using a clear, repeatable quarterly checklist reduces surprises at year-end and protects you from reassessment.

LEGAL AND REGULATORY FRAMEWORK

GST is governed by the federal Excise Tax Act and QST by the Quebec Taxation Act. Businesses assigned a quarterly reporting period must file a combined GST/QST return for each quarter and remit any balance owing by the prescribed deadline. The return must accurately report taxable supplies, zero-rated supplies, exempt supplies, tax collected or collectible, input tax credits and input tax refunds, and adjustments.

Revenue Québec requires registrants to keep detailed records of sales, purchases, and tax calculations for at least six years. Quarterly preparation must align with these legislative requirements. The amounts reported on your quarterly returns should match your accounting records, POS summaries, and bank activity.

KEY COURT DECISIONS

Courts have repeatedly held that taxpayers are responsible for maintaining accurate periodic tax records and filing timely, correct returns. In disputes where quarterly filings did not match underlying documentation, judges upheld reassessments from Revenue Québec and CRA. Courts emphasized that estimates, guesswork, or incomplete records are not acceptable substitutes for proper evidence.

In cases where taxpayers attempted to “fix” several past quarters at once without adequate support, the courts sided with the tax authorities. These decisions underline the importance of disciplined quarterly preparation rather than waiting until year-end to reconcile GST/QST accounts.

WHY CRA AND REVENU QUÉBEC TARGET QUARTERLY FILERS

Quarterly filers are closely monitored because cash flows and sales can fluctuate significantly from one quarter to another. Red flags for Revenue Québec include large or irregular refund claims, sudden drops or spikes in taxable sales, inconsistent QST versus GST reporting, and recurring late filings. Businesses that rush through quarterly filings without following a checklist are more likely to make mistakes.

Industries with seasonal activity, construction progress billing, deposit-based projects, or high-volume retail sales often encounter quarterly variances. These sectors are more likely to attract questions from Revenue Québec when quarterly filings do not follow normal patterns.

QUARTERLY GST/QST PREP CHECKLIST: TASKS EVERY 3 MONTHS

1. Review your quarterly calendar
   Confirm the exact start and end dates of your reporting period. Note the filing and payment deadlines in your agenda and internal task list. Make sure you know which months belong to the current quarter and verify that no transactions have been recorded in the wrong period.

2. Reconcile sales and revenue
   Compare your total sales for the quarter from your accounting software, POS system, and bank deposits. Separate taxable sales, zero-rated sales, and exempt sales. Identify any unusual entries, negative invoices, or manual adjustments that may affect your GST/QST totals.

3. Verify tax collected on sales
   Run a report showing GST and QST charged on all invoices and sales receipts for the quarter. Ensure that tax rates are correct and that each taxable sale has GST/QST coded properly. Look for transactions where tax was manually overridden or set to zero when it should not have been.

4. Review input tax credits and refunds
   Extract a list of all expenses for which you are claiming input tax credits. Confirm that each supplier invoice shows the correct legal name, GST and QST registration numbers, tax amounts, and clear descriptions of goods or services. Exclude personal expenses and non-eligible purchases.

5. Check for missing or duplicate invoices
   Scan your records for gaps in invoice numbers, missing supplier bills, or duplicated entries. Request missing invoices from vendors before finalizing your quarterly GST/QST return. Remove any duplicates that could lead to overstated credits.

6. Reconcile GST/QST control accounts
   Compare the balances in your GST collected, QST collected, and input tax credit accounts against your detailed sales and purchase reports. Any difference between ledger balances and transaction reports should be investigated and corrected.

7. Record adjustments, credit notes, and bad debts
   Gather all credit notes, returns, rebates, discounts, bad debt write-offs, and cancellations related to the quarter. Ensure that these adjustments are reflected in both your sales totals and your GST/QST calculations. Properly code bad debt adjustments when tax has already been remitted.

8. Review cash versus accrual issues
   Make sure that your GST/QST reporting basis matches the method assigned by Revenue Québec. If you file on an accrual basis, tax is calculated when the invoice is issued. If on a special method, verify that receipts and invoices are treated consistently. Avoid mixing cash and accrual without clear documentation.

9. Complete and review the FPZ-500-V return
   Transfer your quarterly totals carefully to the FPZ-500-V combined GST/QST return. Double-check lines for total sales, tax collected, input tax credits, adjustments, and net tax payable or refundable. Compare the draft return to your internal summary report to ensure that no category has been omitted.

10. Plan and execute your payment or refund follow-up
    If your return shows a balance owing, plan your payment to Revenue Québec before the deadline and ensure sufficient funds are available. If a refund is expected, keep an audit-ready file including invoices, summaries, and reconciliations in case Revenue Québec reviews your claim. Monitor your online account to confirm receipt and processing.

Following this checklist every quarter builds a strong compliance routine and minimizes the risk of surprises or audits.

MACKISEN STRATEGY

Mackisen CPA helps businesses structure their quarterly GST/QST workflow using clear checklists, reconciliations, and internal controls. Our team reviews your sales, expenses, and tax coding every quarter, identifies errors early, and prepares or reviews your FPZ-500-V filings for accuracy. We configure your accounting system to produce quarterly reports that line up directly with the return.

We also set up quarterly calendars, reminder systems, and documentation templates so your staff know exactly what needs to be done at each quarter-end. For businesses that have fallen behind, Mackisen prepares catch-up filings and negotiates with Revenue Québec where necessary.

REAL CLIENT EXPERIENCE

A small e-commerce business filed quarterly but never reconciled GST/QST control accounts. When a refund was held for review, they could not easily produce documentation. Mackisen reconstructed their quarterly reconciliations, organized invoices, and the refund was released.

A construction contractor with milestone billing had inconsistent quarterly GST/QST filings because deposits and progress invoices were coded differently. Mackisen standardized their invoicing process, aligned revenue recognition with tax treatment, and stabilized their quarterly returns.

A service firm regularly rushed quarterly filings at the last minute. Errors accumulated over several periods. Mackisen implemented a quarterly checklist, created internal deadlines ahead of the remittance date, and reduced discrepancies to almost zero.

COMMON QUESTIONS

Do all businesses file GST/QST quarterly
Not all. Some file monthly or annually depending on revenue. Quarterly filers must follow their assigned frequency unless a change is requested and approved.

Can I switch from quarterly to annual filing
Sometimes. It depends on your revenue level and approval from Revenue Québec and CRA. A CPA can help evaluate and request a change.

What if I miss a quarterly filing deadline
Penalties and interest may apply. Repeated late filings increase the likelihood of an audit.

Should I reconcile monthly even if I file quarterly
Yes. Monthly reconciliation helps catch errors early and makes quarterly filing much easier.

What if my quarterly return shows a large refund
Large refunds often trigger reviews. Keep a complete audit-ready file with invoices and reconciliations.

WHY MACKISEN

With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps businesses handle quarterly GST/QST obligations with confidence. Whether you need a structured checklist, complete filing support, or help cleaning up past quarters, our team ensures precision, transparency, and protection from reassessment risk.