A BC business is required to register for GST once its worldwide taxable revenue exceeds $30,000 in a single calendar quarter, or across four consecutive calendar quarters. Below that threshold the business is a "small supplier" and registration is voluntary. Many businesses register voluntarily below the threshold to recover input tax credits on business purchases — whether that pays off depends on how much GST the business actually pays on its inputs and who its customers are.
The $30,000 small-supplier threshold in plain language
The number is cumulative and rolling. You cross the threshold the moment your trailing four-quarter taxable revenue exceeds $30,000, or your single-quarter taxable revenue does. From that day, you have 29 days to register with the CRA and begin charging GST. Miss the window and the CRA can charge you retroactively — you owe the GST you should have collected, whether or not you actually did.
Two specific misreadings catch people out. First, the $30,000 is total taxable revenue across all commercial activity, not net profit or taxable income. Second, zero-rated supplies (exports, most groceries) count toward the threshold even though no GST is collected on them.
The case for voluntary registration below $30,000
Registering before you have to makes sense in three situations.
You spend meaningfully on GST-registered suppliers. If your business regularly pays GST on significant inputs — software subscriptions, professional fees, equipment, commercial rent — registration lets you claim input tax credits (ITCs) and recover that GST. For a consulting business with $5,000 a month in GST-registrant expenses, registration recovers $3,000 per year.
Your customers are businesses, not consumers. If you bill other businesses, they recover the GST you charge through their own ITCs. Charging GST costs them nothing and you recover the GST you pay on your inputs. This is the cleanest case for voluntary registration.
You are about to cross the threshold anyway. If revenue is growing and the threshold is three to six months away, voluntary registration avoids the awkward mid-year price change when you start charging GST on existing invoices.
The case against registering early
Voluntary registration adds administrative overhead and, if your customers are individuals, raises your effective price by 5%. For a sole proprietor selling direct to consumers under $30,000 in revenue with negligible input GST, registering voluntarily is pure downside. The CRA's own guidance does not push small suppliers to register — small-supplier status exists specifically to exempt these businesses from the filing burden.
How to register with the CRA
The registration mechanics are straightforward but the sequence matters.
Step 1 — Get a Business Number (BN). If the business does not already have a nine-digit BN from incorporation or payroll, register one through the CRA's Business Registration Online (BRO) portal. Incorporated businesses typically already have a BN assigned at the point of incorporation.
Step 2 — Add a GST/HST program account (RT0001). Through CRA My Business Account or by calling the CRA business line, add an RT program account to the BN. This is the account that will file GST returns.
Step 3 — Set the reporting period. The CRA assigns a default reporting frequency based on expected taxable revenue: annual for under $1.5M, quarterly for under $6M, monthly above $6M. You can request a different frequency in writing — many small businesses benefit from quarterly filing even when annual is available, because it keeps ITCs flowing back more often.
Step 4 — Choose a fiscal year-end. For GST purposes, this usually mirrors the business's fiscal year. For incorporated businesses the fiscal year is whatever was elected at incorporation.
Step 5 — Start charging GST on the effective registration date. From that date, every taxable sale must include GST, every invoice must show the GST number, and every input GST paid is claimable.
For the full reference on GST and PST filing mechanics end-to-end — registration, ITCs, filing frequencies, and penalties — see the GST and PST filing guide for BC businesses.
What to do on the first GST return after registration
Two things that are easy to miss.
Claim pre-registration ITCs. For capital property and inventory on hand at the moment of registration, ITCs can be claimed for GST paid before the registration date. Most small businesses miss this — it is worth 5% on the stock and equipment sitting in the business at the moment the registration takes effect.
Reconcile filed GST to the ledger. The first quarterly return usually has errors: tax codes in QuickBooks or Xero misconfigured, transactions from the pre-registration period accidentally included, or input credits claimed on non-business purchases. A proper close after the first filing catches these before the CRA does.
PST is separate — do not confuse the two
GST registration with the CRA does not register you for BC Provincial Sales Tax. The BC Ministry of Finance administers PST through eTaxBC under an entirely separate registration process. If your business sells taxable goods or taxable services in BC, you register for PST separately, typically once you begin selling — there is no $30,000 threshold for BC PST.
For the difference between the two taxes, see PST vs. GST in British Columbia.
Common mistakes that cost time
Three recurring errors we see when BC businesses register without professional help.
Registering the wrong entity. The sole proprietor registers their personal BN for GST, then incorporates six months later and operates under the new corporation, leaving the GST number attached to a dormant sole proprietorship. Fix: register GST under the entity that will actually invoice customers.
Late effective date. Registering today but backdating the effective date to January 1 to claim ITCs. The CRA permits limited backdating, but the business then owes GST on sales made in the backdated period — often more than the ITCs recovered.
Not updating invoicing immediately. The registration is complete, but invoices still go out without GST line items. Every such invoice is non-compliant and has to be reissued. Check the QBO or Xero tax settings on the day registration takes effect.
When to get help
For most BC owner-operators, GST registration is a twenty-minute exercise once the sequence is clear. The complications come later — filing late, claiming ITCs incorrectly, or handling PST on the same ledger. If you are registering because you are already behind, a catch-up engagement to clean up the backfiled periods usually costs less than the CRA interest on getting it wrong.
If you are adding GST to an existing monthly close, GST and PST filing handles the returns alongside your books — registration, ongoing filing, and ITC reconciliation as one workflow.
Where to read more
- CRA's business number and GST/HST registration guide for the official registration mechanics.
- Coal Harbour's post on what GST and PST filing is in BC for the definition-level primer.
Registration is the easy part. The filings that follow are where discipline starts to matter — file them on schedule, reconcile them against clean books, and GST stops being a source of anxiety.