How to Calculate GST/HST (and Reverse It) in Every Province

Short answer: To calculate GST or HST, multiply the pre-tax price by the rate for the province where the supply is made: 5% GST, 13% HST in Ontario, 14% in Nova Scotia and 15% in New Brunswick, Newfoundland and Labrador and Prince Edward Island. The total is price × (1 + rate). To back the tax out of a tax-included total, divide by (1 + rate) to get the price; the difference is the tax. In a PST province, work each tax out on the pre-tax price, never one on top of the other.

These are the rates in force in 2026, from the Canada Revenue Agency’s (CRA) GST/HST rates and calculator page and the provinces’ own sites, and the arithmetic is the same whether you are pricing a job, checking a supplier’s bill or preparing a return. You only charge GST/HST once you are registered (see how to register for GST/HST), and Quebec’s GST-plus-QST maths has its own page, Quebec sales tax for contractors. This page has no calculator; it gives you the formulas, so any calculator, spreadsheet or phone will do.

What are the GST, HST and PST rates by province?

There are three patterns: 5% GST alone, a single HST that already includes the GST, or 5% GST plus a separate provincial sales tax.

Province or territory	Federal or harmonized tax	Provincial tax	Combined on a taxable sale
Alberta, Yukon, Northwest Territories, Nunavut	5% GST	None	5%
British Columbia	5% GST	7% PST (general rate)	12%, as two separate taxes
Saskatchewan	5% GST	6% PST	11%, as two separate taxes
Manitoba	5% GST	7% RST	12%, as two separate taxes
Quebec	5% GST	QST	See the Quebec page
Ontario	13% HST	Included in the HST	13%
Nova Scotia	14% HST (since April 1, 2025)	Included in the HST	14%
New Brunswick, Newfoundland and Labrador, Prince Edward Island	15% HST	Included in the HST	15%

The GST and HST rates are the CRA’s. The provincial rates come from each province: British Columbia’s PST is generally 7%, with different rates for a few items such as accommodation and liquor; Saskatchewan’s PST is 6%; and Manitoba’s retail sales tax is 7%. Provincial sales taxes are run by the provinces, not the CRA, and decide for themselves what is taxable. Contractors in particular should read the provincial rules before adding a PST line, as British Columbia sales tax for contractors shows.

How do you calculate GST/HST on a price?

Multiply the pre-tax price by the rate to get the tax and add it, or multiply the price by (1 + rate) to get the total in one step.

• Tax = price × rate
• Total = price × (1 + rate)

Pre-tax price	Province	Rate	Tax	Total
$1,000	Alberta	5%	$50.00	$1,050.00
$1,000	Ontario	13%	$130.00	$1,130.00
$1,000	Nova Scotia	14%	$140.00	$1,140.00
$1,000	New Brunswick	15%	$150.00	$1,150.00
$2,480	Ontario	13%	$322.40	$2,802.40

Write the rate as a decimal when you multiply: 13% is 0.13, so the multiplier for an Ontario total is 1.13, and for GST alone it is 1.05. Work the tax out on the invoice subtotal and round the result to the cent.

How do you reverse calculate GST/HST from a total?

Divide the tax-included total by (1 + rate) to get the pre-tax price; the tax is the total minus that price.

• Pre-tax price = total ÷ (1 + rate)
• Tax included = total − pre-tax price, which is the same as total × rate ÷ (100% + rate)

Worked example (Ontario, 13%). A supplier receipt says $565.00 including HST. $565.00 ÷ 1.13 = $500.00 before tax, so the HST is $65.00.

Worked example (Alberta, 5%). You quoted a client “$2,100 all in.” $2,100 ÷ 1.05 = $2,000.00, so your fee is $2,000 and the GST is $100.00.

The second formula is the one the CRA uses when it tells registrants to calculate input tax credits from a tax-included amount: multiply by 5/105 for purchases taxed at 5% GST, or 13/113 for 13% HST. The same pattern gives 14/114 in Nova Scotia and 15/115 at 15%. The mistake to avoid is taking 13% of the total: 13% of $565 is $73.45, which overstates the tax by $8.45 because it taxes the tax.

How do you calculate GST and PST together?

Work out each tax separately on the same pre-tax price and add both to the price; do not charge one tax on top of the other.

Manitoba spells this out: its retail sales tax is calculated on the selling price before the GST is applied. On $800 of taxable goods:

Province	GST (5%)	Provincial tax	Total
British Columbia	$40.00	PST 7%: $56.00	$896.00
Saskatchewan	$40.00	PST 6%: $48.00	$888.00
Manitoba	$40.00	RST 7%: $56.00	$896.00

To reverse a combined total, divide by 1 plus both rates together: a British Columbia total of $896 ÷ 1.12 = $800 before tax, so $40 is GST and $56 is PST. Keep the two taxes on separate invoice lines, because they go to different governments and only the GST can come back to a registered client as an input tax credit. Quebec follows its own sequence, so use the worked examples on the Quebec page rather than these.

Which province’s rate do you charge?

Generally the rate of the province where the supply is made, which for most services is the province of the client’s address, not where you live.

Under the CRA’s place-of-supply rules, a service is generally supplied in the province of the client’s home or business address that you get in the normal course of business. An Ontario freelancer billing a client based in Alberta would therefore usually charge 5% GST, not 13% HST. Services in relation to real property are the big exception: they follow where the property is, so a Nova Scotia contractor renovating a house in New Brunswick charges New Brunswick’s 15%.

Getting this wrong costs you either way. Charge too little and you still owe the right tax; charge too much and your client pays tax they never owed. The tax on your invoices is also the tax you report, so these totals end up on line 103 when you file your GST/HST return.

How do you check the GST/HST on your own records?

Divide the tax on each invoice by its pre-tax amount and check you get the rate you meant to charge; on receipts, use the tax fraction to test that the tax shown is plausible.

On an Ontario invoice, $322.40 ÷ $2,480 = 0.13, as it should be. A result like 0.115 usually means a mixed invoice or a typing error. On a $226 receipt from an Ontario supplier, 13/113 of $226 is $26, so a receipt showing $26 of HST is consistent. When you claim input tax credits, claim the tax the supplier’s document actually shows, and keep that document. What a valid receipt needs is covered in self-employed expenses and receipts.

…and where does Keel fit?

Keel: Invoice Maker & Receipts, an iPhone app by Ilura Technology, keeps the estimates, invoices and receipts these calculations come from, each kept under its job, so you can check the tax on any document later. It is a record keeper: it does not decide which rate applies to you, does not calculate the tax you owe for a province, and does not file returns or connect to the CRA.

Records stay on your iPhone, with no account, no bank connection and no cloud sync, and the App Store privacy label reads “Data Not Collected.” Keel is free with no invoice limit (free invoices carry a small “Made with Keel” footer); Keel Lifetime is a one-time purchase ($249.99 USD, local price on the App Store) that adds custom branding, a signature, premium templates and accountant-ready exports. Keel: Invoice Maker & Receipts on the App Store.

Frequently asked questions

How do I reverse calculate HST in Ontario? Divide the tax-included total by 1.13 to get the price before tax, then subtract that from the total to get the HST. For example, $1,130 ÷ 1.13 = $1,000, so the HST is $130. You can also multiply the total by 13/113, the fraction the CRA uses for amounts that include 13% HST. Do not take 13% of the total, because that overstates the tax.

Is HST charged on top of PST? No province charges both. HST provinces have one combined tax that already includes the 5% GST. In British Columbia, Saskatchewan and Manitoba, the GST and the provincial tax are each calculated on the pre-tax price and shown as separate lines, so neither tax is charged on the other. Quebec has its own rules for GST and QST, explained on the Quebec sales tax page.

How much is GST on $100? At the 5% GST rate, the tax on $100 is $5, for a $105 total. In Ontario the 13% HST would be $13, in Nova Scotia the 14% HST $14, and in New Brunswick, Newfoundland and Labrador or Prince Edward Island the 15% HST $15. Use the rate of the province where the supply is made, which for most services is where your client is.

Do I have to charge GST/HST if I am a small business? Only once you are registered. You are a small supplier, with no obligation to register, while revenue from your worldwide taxable supplies (and your associates’) is $30,000 or less in a single calendar quarter and over the last four consecutive calendar quarters, according to the CRA’s general information for registrants. You can still register voluntarily, and once registered you calculate the tax exactly as shown above.

What is the formula to calculate GST and PST together? Calculate each tax separately on the pre-tax price and add both: price × GST rate, plus price × PST rate. In British Columbia, $500 of goods taxed at the general rate carries $25 of GST and $35 of PST, for a $560 total. To reverse a combined total, divide it by 1 plus both rates, so $560 ÷ 1.12 = $500 before tax.

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This article is general information, not tax advice. Consult a qualified accountant or tax professional.