When Must a Business Register for GST/HST?

The threshold is based on taxable supplies, not profit

A business can have little or no accounting profit and still exceed the GST/HST small-supplier threshold because the test generally looks at revenue from taxable supplies before expenses. Zero-rated supplies are generally included in taxable supplies, while exempt supplies require separate treatment.

A sole proprietor must also consider taxable supplies from associated business activities under the same legal person rather than viewing each trade name in isolation.

The two threshold tests

The timing differs depending on how the threshold is exceeded.

Single calendar quarter. If taxable supplies exceed the ordinary threshold in one calendar quarter, small-supplier status can end immediately. The transaction that pushes revenue over the threshold may be treated differently from the rolling test.

Four consecutive calendar quarters. If the total exceeds the threshold over four consecutive quarters but not in a single quarter, small-supplier status generally ends later under the timing rules. The business needs a quarterly schedule to identify the effective date.

Worked example

A consultant records taxable sales of $9,000, $8,500, $7,500 and $8,000 over four consecutive calendar quarters. Total taxable supplies are $33,000. The consultant did not exceed $30,000 in any one quarter, but the rolling four-quarter total passed the threshold.

The consultant should not simply begin charging tax on the first day the spreadsheet total looks high. The exact effective date and registration deadline should be confirmed under the rolling-quarter rules. Invoices issued around that date must be reviewed so tax is not missed or charged too early.

What changes after registration

A registrant generally needs to charge the correct GST or HST on taxable supplies, show required information on invoices, file returns even for nil periods, remit net tax and preserve records. In return, it may claim input tax credits for eligible tax paid on costs used in commercial activities.

Sales tax collected is not revenue available for personal spending. It should be tracked in a liability account and reconciled to each return.

Voluntary registration before the threshold

A business below the threshold may choose to register. That can be useful where startup costs contain significant GST/HST or customers are primarily registered businesses that can recover the tax. It may be less attractive for price-sensitive consumers who cannot claim input tax credits.

Voluntary registration creates real obligations. The business should be ready to issue compliant invoices, maintain records and remain registered for the required period.

Quarterly monitoring process

Maintain a schedule by legal entity showing taxable supplies for each calendar quarter and the rolling four-quarter total. Add a reminder when cumulative sales approach the threshold. Review unusual items such as asset sales, foreign customers, exempt services and reimbursements separately.

Waiting for year-end bookkeeping can cause a business to discover registration months late, creating tax owing that may be difficult to collect from customers afterward.