Tax and CRA deadlines
Ontario HST calculator
Add 13% to a price, or pull the HST back out of a total.
A starting point, not tax advice. Nothing you type leaves your browser.
How this works
What the number means
Ontario's HST is 13% — 5% federal GST plus an 8% provincial portion, charged as a single tax.
Adding it is straightforward: multiply by 1.13. Taking it back out of a total is where people slip, because 13% of the total is not the HST inside it. You divide by 1.13 to get the pre-tax amount, then subtract.
Worked example. A $500 invoice becomes $565.00 with HST. Going the other way, a $565.00 total contains $500.00 of work and $65.00 of HST — not $73.45.
Sources
- CRA — Charge and collect the GST/HST: which rate to charge — modified 8 April 2026
Rates change. The CRA page is the authority, and these are reviewed every January.
Questions
When do I have to register for GST/HST?
Once your taxable revenue passes $30,000 over four consecutive calendar quarters. If you pass $30,000 within a single quarter, you must register within 29 days of the sale that took you over. The CRA sets both rules.
Next step
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