Short answer
GST/HST has four filing frequencies (monthly, quarterly, annual non-individual, annual sole-proprietor), with deadlines that depend on the client's reporting period end rather than the calendar. Most CPA firms have a mix of all four across their book — which is exactly why it gets missed. The fix isn't to remember harder; it's to track GST/HST per-client with frequency-aware auto-calculated deadlines.
Why GST/HST gets missed more than any other filing
Three reasons, all related:
- Frequencies vary across your client base. One client files monthly; another quarterly; another annually. There is no "March 31 GST deadline" — there are 200 different GST deadlines depending on each client's reporting period
- Period-ends drift. When a client crosses a threshold and the CRA moves them from quarterly to monthly, your tracker doesn't automatically know. The next quarter you're not expecting a return — they're already late
- It's never the loud one. T1 forces itself into your attention every April. GST is quieter, until it isn't
A composite from a 5-partner firm in Vaughan: in 2024 they reviewed three years of GST/HST filings across their client base and found 8 returns that had been filed late (median: 47 days late). Total CRA penalties and interest paid by clients: just over $19,000. None of it was caught at the time — it surfaced only because they did a multi-year audit.
The four GST/HST filing frequencies
The CRA assigns frequency based on annual taxable supplies. Higher revenue = more frequent filing.
| Frequency | Threshold | Filing & payment due |
|---|---|---|
| Monthly | > $6M annual taxable supplies | 1 month after period end |
| Quarterly | $1.5M – $6M | 1 month after period end |
| Annual (non-individual) | ≤ $1.5M (corporations, partnerships, trusts) | 3 months after fiscal year-end |
| Annual (sole proprietor) | ≤ $1.5M (individuals) | Filing: June 15. Balance: April 30 |
The "1 month after period end" for monthly and quarterly is universal — you can't get out of it. For example:
- Monthly filer with March 31 period-end: file and pay by April 30
- Quarterly filer with January 31 period-end (a non-calendar fiscal year): file and pay by February 28
- Annual non-individual with August 31 fiscal year-end: file and pay by November 30
For a deeper view of all CRA filing types and their deadlines, see How to Track Every CRA Deadline in 2026.
What "reporting period" actually means
This trips up firms more than it should. A client's GST reporting period is not always the calendar quarter. It can be a calendar quarter, but it can also be a non-calendar fiscal-year-aligned quarter.
Example: a corporation with a fiscal year ending August 31, on quarterly filing, has reporting periods of:
- September 1 – November 30 (Q1)
- December 1 – February 28 (Q2)
- March 1 – May 31 (Q3)
- June 1 – August 31 (Q4)
Their GST returns are due December 31, March 31 (or 30 in non-leap years), June 30, and September 30 — none of which match the "calendar GST quarterly" dates of April 30, July 31, October 31, January 31.
This is why a master "GST due — Q1 — April 30" reminder column in a spreadsheet doesn't work for firms with fiscal-year-aligned clients. The deadline is per-client, computed from their actual reporting period.
Instalments: another layer to track
Annual filers with prior-year net GST/HST owing of $3,000 or more must make quarterly instalments. The instalment amount is the lower of:
- 1/4 of the prior year's net GST/HST owing, or
- 1/4 of the current year's expected net GST/HST owing
Instalments are due one month after each quarter-end of the fiscal year. For a calendar-year sole proprietor: instalments due April 30, July 31, October 31, January 31, with the annual return reconciling everything by June 15 (filing) and April 30 (balance).
Instalment tracking is its own per-client schedule. If you have 30 annual GST clients with instalments, that's 120 instalment due dates per year on top of the 30 annual filings. None of which match each other unless their fiscal years happen to align.
The Quick Method (and when it saves the client real money)
The Quick Method is a simplified accounting method available to eligible small businesses. Instead of tracking every input tax credit, the business remits a fixed percentage of GST/HST-included sales. The applicable rate depends on:
- Type of business — service-based vs goods-reselling
- Province — different rates in HST provinces (Ontario, Atlantic Canada) vs GST-only provinces vs Quebec (QST)
Quick Method eligibility:
- Annual taxable supplies (current and prior 4 quarters) ≤ $400,000
- Not in certain ineligible categories (financial institutions, charities, listed professions in some cases)
- Must elect to use the Quick Method using Form GST74
For a service-based consultant with $200K in revenue and minimal expenses, the Quick Method can save real dollars annually. The CPA's role is to identify eligible clients, run the cost-benefit analysis, and elect at the right time.
This is exactly the kind of advisory opportunity that gets missed when GST/HST tracking is an Excel afterthought rather than part of the firm's core operating system.
Common mistakes firms make with GST/HST
1. Tracking calendar quarters instead of client periods
The "April 30, July 31, October 31, January 31" mental model only works for calendar-year filers. Every fiscal-year client breaks it. The fix: store each client's reporting period start, frequency, and let the system compute the next due date.
2. Forgetting the threshold-crossing event
When a client's annual taxable supplies cross $1.5M, the CRA reassigns them from annual to quarterly (or quarterly to monthly at $6M). This usually triggers a CRA letter. If your firm doesn't see that letter promptly, you're tracking the old frequency. Three months later you find out you missed two quarterly returns.
The defense: review each GST client's frequency annually as part of year-end work. If revenue crossed a threshold, expect the CRA to change them, and update your tracker proactively.
3. Mixing up filing date and balance date
For most filers, filing and payment are due on the same day. But for sole proprietors filing annually: filing is due June 15, balance is due April 30. Late payment penalties accrue from May 1 even if the return was filed on time. This catches firms that "filed by June 15" but didn't push the client to pay April 30.
4. Treating instalments as optional
Instalments aren't a request — they're required for annual filers with $3K+ prior-year owing. CRA charges interest on missed instalments. Firms that treat instalments as "we'll figure it out at year-end" cost their clients money.
5. Not advising on Quick Method eligibility
Eligible service-based clients on the regular method are leaving real money on the table. The Quick Method election needs to be filed; it's not automatic. If your firm doesn't have a process to evaluate Quick Method eligibility for every new and existing client, you're missing a value-add.
Building a GST/HST tracking system that scales
What to capture per client
- GST/HST registration number
- Registration effective date
- Filing frequency (monthly / quarterly / annual non-individual / annual sole-prop)
- Reporting period start (e.g., "fiscal year starts September 1")
- Quick Method status (yes/no, election date)
- Instalment requirement (yes/no based on prior year)
- Last filed period
What the system should auto-compute
- Next reporting period end date
- Next filing due date (period end + 1 month for monthly/quarterly; year-end + 3 months for annual non-individual; June 15 / April 30 split for sole proprietor)
- Next instalment due date (if applicable)
- Threshold-crossing alert (if revenue trends toward a frequency change)
What the system should auto-remind
- Client: "your GST quarter is ending in 14 days; please send us your sales/expense summary"
- Staff: "GST return for client X is due in 7 days and not started"
- Partner: "GST instalment overdue for client Y"
This is exactly the system MyCPACRM's tax filing module implements for GST/HST: configurable frequency per client, auto-calculated reporting periods and deadlines, integration with automated reminders, and surfacing on the main dashboard alongside every other filing type.
How MyCPACRM handles GST/HST end-to-end
MyCPACRM tracks GST/HST as a first-class filing type — not a free-text note on a client. Each client's GST configuration includes registration number, frequency, reporting-period start, Quick Method status, and instalment requirement. The system auto-computes every upcoming filing and instalment, fires reminders to clients and staff on a schedule you configure, and shows everything on the unified workflow dashboard alongside T1, T2, T4, payroll, and the rest. Reminder cadences are customizable per filing type — you can have a different sequence for GST quarterly vs T1 annual.
For firms used to "GST tracking is wherever Sarah keeps it," the difference is immediate: every staff member can see every GST deadline for every client they touch, every day, without asking.
Frequently Asked Questions
How is GST/HST filing frequency determined?
The CRA assigns filing frequency based on annual taxable supplies: monthly (over $6 million), quarterly ($1.5M to $6M), or annual (under $1.5M). Businesses can elect a more frequent filing schedule than the CRA assigns, but cannot elect a less frequent one.
When is the GST/HST return due for a quarterly filer?
One month after the end of the reporting period. A quarterly filer with a March 31 period-end has until April 30 to file and pay. The same one-month rule applies to monthly filers.
What is the deadline for GST/HST annual filers?
For annual filers (non-individual), the return is due 3 months after the fiscal year-end, with payment also due at that time. For sole proprietors filing annually, the return is due June 15 but any balance owing is due April 30.
What is the GST/HST Quick Method?
The Quick Method is a simplified accounting method for eligible small businesses where, instead of tracking every input tax credit, the business remits a fixed percentage of GST/HST-included sales. The applicable percentage depends on the business type and province. Most service-based small businesses with under $400,000 in taxable supplies are eligible.
Can a business change its GST/HST filing frequency?
Yes — a business can elect more frequent filing (e.g., quarterly to monthly) at any time. To file less frequently than the CRA-assigned default, the business must apply and meet the threshold. The change typically takes effect at the start of the next fiscal year.
Are GST/HST instalments required?
Annual filers with net GST/HST owing of $3,000 or more in the prior year must make quarterly instalments. The instalments are typically 1/4 of the prior year's net GST/HST or 1/4 of the current year's estimate, whichever is lower. Instalments are due one month after each quarter-end.