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Tax

Do I need to register for HST in Ontario?

TSL Written by the Treadstone Law team· Updated June 2026

In Ontario, you are generally required to register for HST — which combines the federal GST and Ontario's provincial component — once your total taxable revenues exceed $30,000 over four consecutive calendar quarters or in a single calendar quarter. Until you cross that threshold, you are considered a "small supplier" and registration is optional.

If you stay below $30,000, you can still register voluntarily. Voluntary registration lets you claim input tax credits (ITCs) on the HST you pay for business expenses, which is often worthwhile even at lower revenue levels.

Some suppliers — such as taxi and ride-sharing operators — must register regardless of revenue. Charities, public service bodies, and certain professionals face different rules. Because the threshold and exemptions depend on how your revenue is calculated and what you sell, speaking with a tax lawyer or accountant before deciding is worthwhile.

Key takeaways

  • The mandatory registration threshold is $30,000 in taxable revenues over four quarters.
  • Below $30,000 you can still register voluntarily to claim input tax credits.
  • Certain industries must register regardless of revenue.
  • How you calculate "revenue" matters — get professional advice before deciding.
This is general information, not legal advice. It doesn’t create a lawyer–client relationship, and the rules can change. For advice on your situation, a Treadstone tax lawyer can help.
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