1. Are you registered correctly?

Registration is where most HST issues start. If you crossed $30,000 in revenue and did not register in time, CRA can go back and charge you the HST you never collected.

Revenue hit $30,000 in any single calendar quarter, or across 4 rolling quarters.
Registered within 29 days of hitting that threshold.
Business Number active on your CRA My Business Account.
Right filing frequency for your revenue — monthly above $6M, quarterly $1.5M–$6M, annual below $1.5M.
Voluntary early registration considered if you had big startup costs with HST on them.

2. Are you charging the right amount?

Ontario HST is 13% — the 5% federal GST and the 8% provincial portion rolled into one line. The errors live in what you do with mixed or cross-border sales.

13% HST charged on every taxable sale delivered in Ontario.
Zero-rated sales (basic groceries, prescription drugs, exports) kept separate from taxable on your books.
Every invoice and POS receipt shows HST as its own line item.
Cross-border sales handled by place-of-supply rules (which province the customer is in decides the rate).
Mandatory service charges (18% gratuity added to the bill) treated as taxable; voluntary tips treated as not taxable.
Your HST number printed on every invoice over $30.

3. Are you claiming every ITC?

This is the section where we find money. Input tax credits let you get back the HST you paid on business expenses. Most filers leave money on the table here because the categories are easy to miss.

Rent and utilities — gas, hydro, water, internet — the HST portion claimed.
Software subscriptions — QuickBooks, Microsoft 365, Adobe, CRM tools, email — all included.
Vehicle fuel, maintenance, lease payments — business-use portion only.
Professional fees — legal, accounting, consulting, bookkeeping.
Meals and entertainment — 50% of the HST is claimable.
Office supplies, phone bills, cell plans — the business-use portion.
Advertising — Meta, Google, TikTok, print, design fees.
Subcontractor invoices — but only if their HST number is shown.
Capital purchases — equipment, vehicles, furniture — the full HST is claimable in the period you buy.

4. Are you meeting every deadline?

CRA’s rule is one month after the period ends for monthly and quarterly filers. Annual filers get more complicated. Late HST compounds fast so treat this as non-negotiable.

Monthly filers: return and payment due 1 month after the reporting period ends.
Quarterly filers: April 30, July 31, October 31, and January 31 — with shifts for weekends and CRA holidays.
Annual corporate filer: return and payment due 3 months after fiscal year-end.
Annual individual filer (sole prop with Dec 31 year-end): payment due April 30, filing due June 15.

5. Are you ready for a CRA review?

CRA does not warn you before a review. If a letter shows up, you have weeks, not months, to respond. Getting ready in advance turns a review from a panic into paperwork.

Every HST-bearing receipt saved and stored for at least 6 years.
Business Number linked on My Business Account with the right permissions.
Prior-year returns reconciled to your books — not just to what you filed.
Any refund over $10,000 on your last 2 returns — you can explain the cause (big capital purchase, export sale, etc.).
Direct deposit set up so refunds land in days, not weeks.
Your accountant authorized as a representative on My Business Account so they can respond for you.

6. Should you be on Quick Method?

Quick Method lets eligible small businesses remit a flat percentage of HST-inclusive sales instead of tracking ITCs. For most service businesses under $400K it saves $800–$2,000 a year. For some businesses it costs money. Run this section carefully.

Gross sales under $400,000 across the last 4 consecutive quarters.
Service business — remit 8.8% of HST-inclusive sales (Ontario rate).
Goods-reselling business (retail, wholesale) — remit 4.4% of HST-inclusive sales (Ontario rate).
First $30,000 of taxable supplies in a year — 1% credit on what you remit.
Registered for HST at least 1 full year before electing.
Not in an excluded industry — accountants, lawyers, bookkeepers, and financial advisors are not eligible.
Elected by filing CRA form GST74 before the deadline.
Compared Quick Method remittance to regular method on a real quarter before committing.
Still tracking ITCs separately — some capital-ITC claims remain available even on Quick Method.
Eligibility reviewed annually as sales grow toward the $400K ceiling.

Stuck on any of these?

We run this list for every HST client we take on. If you hit a box you can't tick, book a free review. We go through it with you, find what's missing, and tell you what to fix — no pressure to sign up for anything.

Book a Free HST Review