Do I need to charge HST?

The short answer

You need to charge HST (or GST, depending on the province) once your business stops qualifying as a "small supplier" — which, for most businesses, means once your revenue crosses $30,000. Under that line, charging tax is optional. Over it, registering and charging isn't a choice anymore; it's a requirement, and there's a clock on how fast you have to act.

That one number does most of the work here. The rest of this guide is the detail behind it: exactly how the $30,000 test is measured, what rate to charge depending on where your customer is, and why some businesses register voluntarily before they're forced to.

The $30,000 small-supplier test

A business is a "small supplier" — not required to register for GST/HST — if its worldwide taxable-supply revenue is $30,000 or less in a single calendar quarter, and also $30,000 or less across the last four consecutive calendar quarters combined. Stay under both measures and registration is your choice. Exceed either one and it stops being optional.

Here's the part that trips people up: how you cross $30,000 changes when you're on the hook.

• Cross it in a single quarter — one big invoice, one great month — and you become a registrant immediately, on the specific sale that pushed you over. There's no grace period; that transaction itself is taxable.
• Cross it gradually — no single quarter does it alone, but your last four consecutive quarters add up past $30,000 — and your small-supplier status ends at the end of the month following that quarter.

Either way, once you're no longer a small supplier, you must register for a GST/HST account within 29 days of the day your small-supplier status ended. Miss that window and you're still on the hook for the tax you should have been charging — the 29 days is a filing deadline, not a tax-free grace period.

What rate to charge

The rate you charge depends on where the sale happens, not where your business is based. If you're registered and selling to a customer in Ontario, you charge 13% HST — Ontario's combined federal/provincial harmonized rate, with no separate PST layered on top.

Outside Ontario, the rate varies by province:

If you sell across provinces, this means your invoices aren't one-size-fits-all — the tax line changes with the customer's location. It's one of the more common places small businesses get their own books wrong, and exactly the kind of thing a monthly bookkeeping relationship exists to catch before it becomes a filing problem.

Should you register before you have to?

Voluntary registration — signing up before you cross $30,000 — is a real option, and it's not just paperwork for its own sake. The main reason businesses do it is input tax credits: once registered, you can claim back the HST you pay on your own business expenses — software subscriptions, rent, supplies, professional fees — instead of simply absorbing that tax as a cost. For a business with meaningful HST-bearing expenses relative to its revenue, that can genuinely offset the extra administrative work of filing returns.

The trade-off is real too: once registered, you're committed to charging tax on your sales and filing returns on schedule, even in quiet quarters. Whether the input tax credits are worth that commitment depends on your specific expense mix — it's not a universal yes.

Rule of thumb: the more your business spends on HST-bearing overhead relative to what it earns, the more voluntary registration tends to make sense — and the more it's worth actually running the numbers instead of guessing.

Check your own number

Rather than mentally tallying quarters, run your revenue through our free HST checker — it walks through the small-supplier test against your actual numbers and tells you plainly whether you need to register, and by when. If you're already past the threshold and behind on registering, that's worth sorting quickly given the 29-day window above.

And if the honest answer is "I don't know what to charge or when," that's precisely what our monthly bookkeeping is built to take off your plate — HST filings are included in the fee, not billed separately, starting at $200/month.