GST/HST Instalment Due Oct 31, 2026: What You Owe

If you're a self-employed Canadian sitting down with your Q3 numbers this week, there's a date you might be trying to remember: October 31, 2026. That's when your third GST/HST instalment for the year is due to the Canada Revenue Agency (CRA), and if you're an annual GST/HST filer, you're on the hook whether you've been tracking it or not.

For most sole proprietors, incorporated consultants, and small business owners, this deadline arrives quietly. There's no glossy TV ad reminding you. But missing it costs you twice — first in CRA instalment interest, and second, in ways self-employed borrowers rarely see coming, in your ability to qualify for a mortgage.

This guide walks through who owes an instalment, how the CRA calculates the amount, how to pay it before month-end, and why keeping your GST/HST current matters more than most people realize.

— Quick start: pick your path

Here's how to use this article based on where you're standing right now:

Whether you're a first-time buyer planning ahead or a seasoned business owner, the same rules apply: get current, stay current, and treat your CRA account like the financial reference it is.

— Who actually has to make GST/HST instalments

The rule sits inside section 237 of the Excise Tax Act, and it applies to a specific group: annual GST/HST filers. If your business files monthly or quarterly, you remit as you file — no separate instalment obligation kicks in.

Here's what to check. If your net tax owing — the GST/HST you collected minus the GST/HST you paid on business expenses — was $3,000 or more last year, you owe instalments this year. If you expect it to be $3,000 or more this year, the same rule can apply, even if last year was lighter.

Whether you're a rideshare driver, a graphic designer, a Shopify seller, or a licensed trade, the threshold is the same. The label on your business card doesn't matter — the number on your last GST/HST return does.

For a broader look at what to track through the year, our guide on sole proprietor tax planning is a useful companion.

— The 2026 GST/HST instalment calendar

The instalment schedule follows your fiscal year. For most small businesses, that's the calendar year — so the four quarterly deadlines line up with the end of April, July, October, and January.

The table below shows how the 2026 calendar breaks down for calendar-year filers.

If your fiscal year doesn't run January to December (some professional corporations, for example, use a June or September year-end), your instalment dates shift accordingly. The safest way to confirm your personal calendar is inside CRA My Business Account — the online portal shows your exact instalment schedule, the amount the CRA has calculated for you, and any prior payments already applied.

For anyone building or reviewing their financial plain-English glossary, think of an instalment as a partial pre-payment against the tax you'll ultimately owe at year-end — not a separate tax.

— How the CRA calculates your instalment amount

The CRA gives you two ways to calculate each quarterly instalment. The right choice depends on how steady — or how volatile — your business income has been.

The prior-year method, sometimes called the safe-harbour method, takes last year's total net GST/HST owing, divides it into four equal instalments, and pays one each quarter. If your business is steady year over year, this is the simplest option and it protects you from CRA instalment interest almost automatically.

The current-year estimate method works differently. You forecast this year's total net tax owing and pay 25% of that estimate each quarter. This can work better if you expect a lighter year — a client left, revenues dropped — because you don't overpay. The trade-off: underestimate by too much and the CRA charges interest on the shortfall.

If you want to keep your options open, plan on the prior-year method for the first three instalments and reconcile at year-end. Some accountants call this “run the safe path, correct at the finish.” The principle behind our mortgage payment calculator is similar — plan for the higher figure, adjust as reality comes in.

— How to pay your instalment before October 31: a five-step roadmap

Here's the roadmap, in the order most business owners use it.

1. 1
   Confirm the amount.Sign in to CRA My Business Account. Your instalment obligation and the CRA's calculated figure appear under your GST/HST account.
2. 2
   Choose your payment channel.Online banking (add “CRA — GST/HST instalment” as a bill payee), CRA My Payment, pre-authorized debit set up inside My Business Account, or an in-person payment at any Canadian bank with a remittance voucher.
3. 3
   Enter the correct period code.GST/HST payments are applied by period. An October 31 payment coded to the wrong quarter can leave your current instalment showing as unpaid.
4. 4
   Confirm receipt.Payments typically post to your CRA account within three to five business days. Check My Business Account — don't assume.
5. 5
   Reconcile against your books.Match the payment to your bookkeeping the same day. If you're heading toward a mortgage, this is the paper trail lenders quietly appreciate — one more reason working with a broker can pay off later.

— Why unpaid GST/HST can derail your next mortgage

This is the part almost no other publisher covers, and it matters most.

Prime lenders underwrite self-employed borrowers to a stricter standard than salaried applicants. They typically want two years of Notices of Assessment, business financials, and — critically — proof that your CRA account is in good standing across your personal T1 and your business GST/HST and payroll accounts. That proof usually comes from a CRA Statement of Account, listing every balance owing, every payment made, and every filed period.

If that statement shows GST/HST arrears — even from missed instalments the CRA later reconciled — three outcomes are common. Your file may be declined by the A-lender. It may be repositioned with a B-lender at a rate one to three percentage points higher. Or the arrears may need to be paid out at closing directly from your mortgage proceeds, shrinking your usable equity.

As Razi Khan, Founder and Mortgage Broker at Pegasus, sees regularly: borrowers who move smoothly through self-employed approvals treat their CRA account like a credit report — because to a lender, it functions like one.

— Quebec: the parallel QST regime

If your business is registered in Quebec, the mechanics look different. Quebec runs a parallel provincial tax — the Quebec Sales Tax (QST) — and, unlike every other province, Quebec administers both GST and QST together through Revenu Québec, not the CRA.

For Quebec registrants, that means a single combined GST/QST return, a single provincial portal (Revenu Québec's My Account for Businesses), and an instalment schedule set by the province. The $3,000 threshold still applies in spirit, but the exact due dates and calculation methods are Revenu Québec's rules — confirm them directly. Quebec closings also involve notarial steps that can affect current mortgage rate details and timing.

— Six common GST/HST instalment mistakes

A few patterns show up across almost every self-employed file:

• Assuming instalments only apply to incorporated businesses. They apply to sole proprietors and partnerships too, once the $3,000 threshold hits.
• Using the current-year estimate method without tracking sales. Underestimating can trigger CRA instalment interest — the method only works with accurate month-by-month numbers.
• Paying to the wrong CRA account code. GST/HST, payroll, and corporate income tax are separate accounts. A misapplied payment shows the intended account as unpaid until manually corrected.
• Missing the deadline because it fell on a weekend. October 31, 2026 is a Saturday. Payments initiated late Friday can post Monday — check your bank's cut-off.
• Treating instalments as optional when cash-flow tightens. The CRA does not treat them as optional; interest can accrue from day one.
• Forgetting to reconcile at year-end. Missing the reconciliation can lead to unexpected balances owing — and learning about recovery mortgage options after a CRA surprise is the harder path.

— Frequently asked questions

About the author

Razi Khan

Founder, CEO & Licensed Mortgage Broker · Pegasus Mortgage Lending · Toronto, Ontario · FSRA Lic # 11479

Razi Khan is the Founder, CEO, and a licensed Mortgage Broker at Pegasus Mortgage Lending Center Inc., based in Toronto. With over 20 years of experience in the Canadian mortgage industry, Razi has personally guided more than 3,000 clients through some of the most complex and high-stakes financial decisions of their lives — from first-time purchases in the GTA to refinancing strategies, alternative lending solutions, and cross-border mortgages for Canadians buying in the United States.

Razi founded Pegasus in October 2008, launching the brokerage at the height of a global financial crisis. He works across the full spectrum of borrower profiles, with particular expertise in complex files including self-employed borrowers, credit-challenged clients, and investors building multi-property portfolios.

Learn more about Razi Khan →

Sources & references

1. Canada Revenue Agency — Remit (pay) the tax you collected: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/complete-file-return/remit-pay-tax-collected.html
2. Canada Revenue Agency — GST/HST instalment payments: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/complete-file-return/remit-pay-tax-collected/instalment-payments.html
3. Excise Tax Act, R.S.C. 1985, c. E-15, section 237: https://laws-lois.justice.gc.ca/eng/acts/E-15/section-237.html
4. Canada Revenue Agency — Prescribed interest rates: https://www.canada.ca/en/revenue-agency/services/tax/prescribed-interest-rates.html
5. Canada Revenue Agency — My Business Account: https://www.canada.ca/en/revenue-agency/services/e-services/digital-services-businesses/business-account.html
6. Revenu Québec — GST/HST and QST for businesses: https://www.revenuquebec.ca/en/businesses/consumption-taxes/gsthst-and-qst/