How to Calculate HST (2026): Adding, Removing and Reversing GST/HST with Worked C$ Examples

Calculating HST looks like a one-line sum until you have to strip tax out of a receipt, round a long invoice, split GST from PST, or work out what to put on your return. This guide is for owners, freelancers and bookkeepers who want the formulas and the CRA's rules in one place: how to add HST to a price, how to remove it from a total, how the half-cent rounding rule works, how GST + PST and GST + QST differ, how much you can claim back as input tax credits, and how it all lands on the return. Every example uses 2026 rates and real C$ numbers you can check in our Canada GST/HST calculator.

Quick answer

To add HST, multiply the pre-tax price by the rate (×0.13 in Ontario) and add it on — or multiply by 1.13 in one step. To remove HST from a tax-included total, divide by 1 plus the rate (÷1.13); the HST is the difference, or total × 13/113.

• Rates in 2026: 5% GST, 13% HST Ontario, 14% Nova Scotia, 15% NB, NL and PEI

• Never take 13% of a tax-included total — it overstates the tax

• Round to the nearest cent; half a cent or more rounds up

• GST and PST (or QST) are each calculated on the pre-tax price, never on each other

• Your net tax = GST/HST collected − input tax credits on business purchases

The three HST formulas you need

Every GST/HST calculation in Canada is one of three formulas. The only thing that changes is the rate, which depends on the province where the supply is made — usually where you deliver goods or where your client's address is, not where your business is. If you're not sure which rate applies, check our GST/HST rates by province first.

1. Tax on a pre-tax price: HST = price × rate.
2. Total from a pre-tax price: total = price × (1 + rate).
3. Pre-tax price from a total (reverse): price = total ÷ (1 + rate), and the tax = total − price, which is the same as total × rate ÷ (1 + rate).

That last expression — rate ÷ (1 + rate) — is called the tax fraction, and the CRA uses it when you claim tax back from tax-included amounts. In Ontario it's 13/113, about 11.5% of the total.

How to add HST to a price

Adding HST is the calculation you do on every sales invoice. Work out the pre-tax amount first — including any delivery charges you bill as part of the sale and after any discount you give at the time of sale — then apply the rate.

Example — Ontario. A Hamilton bookkeeper bills a local client C$850 for a month of work. HST = C$850 × 0.13 = C$110.50. Invoice total = C$960.50.

Example — Nova Scotia. The same C$850 bill to a client in Halifax: HST = C$850 × 0.14 = C$119.00; total C$969.00.

Example — New Brunswick. To a client in Moncton: HST = C$850 × 0.15 = C$127.50; total C$977.50.

Example — Alberta. To a client in Red Deer: GST = C$850 × 0.05 = C$42.50; total C$892.50.

The pre-tax figure is the number you'll report as revenue, and the tax is money you collect on the government's behalf. That's why most small businesses keep the two in separate accounts in their books. You can show the tax on the invoice as a separate amount, or state that the total includes GST/HST — the CRA accepts either, as long as the customer can tell tax applies. Once a sale reaches C$100, a business customer will also need your GST/HST registration number on the invoice to claim the tax back, so print it on every invoice by default.

Add 13% HST to a C$850 invoice

Add TaxRemove Tax

AmountTax Rate

5% GST (AB, NT, NU, YT)13% HST (ON)14% HST (NS)15% HST (NB, NL, PE)11% GST+PST (SK)12% GST+PST (BC, MB)14.975% GST+QST (QC)

Net Amount (Before Tax)$850.00

Tax (13%)$110.50

Gross Amount (Including Tax)$960.50

Open the full GST/HST Calculator (PDF, save, compare)

How to remove HST from a total (reverse calculation)

Reverse HST calculations come up whenever a price is quoted tax-included: a receipt from a supplier, a menu price at a festival, a fixed-price quote you agreed to "all in", or a bank deposit you need to split into revenue and tax. The rule is simple: divide, don't subtract a percentage.

Example — Ontario, C$500 all-in. C$500 ÷ 1.13 = C$442.477…, which rounds to C$442.48 before tax. HST = C$500 − C$442.48 = C$57.52. Check: C$442.48 × 0.13 = C$57.52, and C$442.48 + C$57.52 = C$500.00.

The mistake to avoid. Taking 13% of C$500 gives C$65.00 — C$7.48 too much. The 13% applies to the pre-tax price, not to a total that already contains the tax. If you've been splitting deposits this way, your books will show too much tax collected and too little revenue; fix it with a journal entry and, if it reached a filed return, an adjustment on the next return.

Same C$500 in other provinces.

• Nova Scotia: C$500 ÷ 1.14 = C$438.60; HST C$61.40
• New Brunswick, Newfoundland and Labrador or PEI: C$500 ÷ 1.15 = C$434.78; HST C$65.22
• Alberta: C$500 ÷ 1.05 = C$476.19; GST C$23.81

Setting an all-in price. If you want a customer to pay exactly C$50 including Ontario HST, the pre-tax price is C$50 ÷ 1.13 = C$44.25, and HST is C$5.75. Because of rounding, the pre-tax price × 1.13 may land a cent off the round figure; adjust the pre-tax price by a cent if you need the total to be exact.

Rounding: the CRA's half-cent rule

GST/HST is calculated to the cent, and the CRA's rule is the familiar one: if the fraction is less than half a cent you may round down, and if it's half a cent or more you round up. Revenu Québec applies the same rule to the QST.

The part people miss is when to round. When a customer buys several items taxed at the same rate, the CRA lets you total the taxable prices first, calculate the tax once and round once. That can produce a different answer from rounding each line.

Example — three C$0.35 items in Ontario.

• Rounding each line: C$0.35 × 13% = C$0.0455 → C$0.05 per item → C$0.15 total HST.
• Rounding once: C$1.05 × 13% = C$0.1365 → C$0.14 HST.

The one-cent difference is trivial on a single sale, but a point-of-sale system that rounds every line can over-collect hundreds of dollars a year on a high-volume coffee counter. Set your till or invoicing software to calculate tax on the subtotal of each tax rate. Items taxed at different rates — say a zero-rated grocery item and a taxable snack — have to be totalled separately before tax is applied.

Cash rounding is different again. Since the penny was withdrawn, cash totals are rounded to the nearest five cents, but only on the final amount after GST/HST has been calculated. The tax on the invoice stays at its calculated, cent-level amount.

How to calculate GST + PST and GST + QST

In British Columbia, Saskatchewan and Manitoba, a taxable sale can attract both the federal GST and a provincial sales tax. The CRA's instruction is to calculate GST on the price without PST, and the provinces calculate PST on the price without GST. So the two taxes are added side by side, never stacked.

BC, C$400 taxable goods. GST 5% = C$20.00; PST 7% = C$28.00; total C$448.00.

Saskatchewan, C$400. GST C$20.00; PST 6% = C$24.00; total C$444.00.

Manitoba, C$400. GST C$20.00; RST 7% = C$28.00; total C$448.00.

To reverse a BC or Manitoba total, divide by 1.12: C$448 ÷ 1.12 = C$400. Then calculate each tax on the C$400 — don't split the C$48 by guesswork.

Quebec, C$400. GST C$20.00; QST 9.975% × C$400 = C$39.90; total C$459.90. Revenu Québec allows either two separate calculations or a single 14.975% rate on the pre-tax price. If a cash register genuinely can't handle three decimals, it may use 9.97% or 14.97% internally, but those rounded rates must never appear on the customer's receipt. To reverse a Quebec total, divide by 1.14975.

Remember that PST and QST only apply when the sale is actually subject to them — many services aren't subject to PST, and a supplier outside Quebec usually charges QST only if registered for it. The arithmetic is the easy part; the hard part is knowing which taxes apply.

Tax on a C$400 taxable sale (2026)

C$420.00

Alberta

5% GST

C$444.00

Saskatchewan

GST + 6% PST

C$448.00

BC / Manitoba

GST + 7% PST/RST

C$452.00

Ontario

13% HST

C$459.90

Quebec

GST + 9.975% QST

C$460.00

NB, NL, PEI

15% HST

Mixed invoices: taxable, zero-rated and exempt items

A single invoice can carry items with different tax treatment. Taxable items take the full rate. Zero-rated items — basic groceries, most prescription drugs, many medical devices and exports — are taxable at 0%: you charge nothing, but the seller can still claim input tax credits on related costs. Exempt items — such as most health and dental services, long-term residential rent and most financial services — are outside the tax entirely, and the seller can't claim input tax credits on costs used to make them.

Example — Toronto convenience store. A customer buys C$12 of milk and bread (basic groceries, zero-rated) and C$8 of chips and soft drinks (snack foods and carbonated drinks are taxable). HST = C$8 × 0.13 = C$1.04, and nothing on the C$12. Total C$21.04. Had the till applied 13% to the whole C$20, it would have charged C$2.60 — C$1.56 too much.

For a business customer, an invoice of C$100 or more that mixes taxable and non-taxable items should show which items are taxable, because the buyer needs that detail to support its input tax credit claim.

Discounts reduce the price the tax is calculated on when you give them at the time of sale. Coupons and early-payment discounts follow more detailed rules, so check the CRA guide before setting them up in your system.

How to calculate the HST you can claim back (input tax credits)

Once you're registered, the GST/HST you pay on business purchases comes back to you as input tax credits (ITCs). Calculating them is the other half of every return.

Regular (detailed) method. Add up the actual GST/HST shown on each eligible purchase invoice for the period. Only the business-use share counts: if a phone plan is used 60% for business, claim 60% of its HST. Meals and entertainment are generally limited to 50% of the tax paid — the CRA lets you claim 50% as you go, or claim 100% during the year and add back the excess at year-end. You have up to 4 years to claim most ITCs, but claiming them in the period they arise keeps cash flow and records simple.

Simplified method. If your annual worldwide taxable revenues are C$1 million or less and your taxable purchases in Canada are C$4 million or less (listed financial institutions excluded), you can skip itemizing the tax. Total your eligible tax-included purchases by rate, then multiply by the tax fraction: 13/113 for Ontario purchases, 5/105 for GST-only purchases, 15/115 for purchases at 15%, and 14/114 for Nova Scotia's 14%. Leave out zero-rated and exempt purchases, and purchases from unregistered suppliers.

Example — an Ottawa renovation contractor, one quarter. Eligible purchases, tax-included: building materials C$15,820, a new saw C$2,260, and a client lunch C$113.

• Detailed method: HST on materials C$1,820 + saw C$260 + 50% of the lunch's C$13 (C$6.50) = C$2,086.50.
• Simplified method: (C$15,820 + C$2,260) × 13/113 = C$2,080.00, plus C$6.50 for the lunch = C$2,086.50.

The answers match because every purchase carried 13%. They diverge when receipts mix rates or include zero-rated items you'd have to strip out.

Each ITC needs supporting paperwork. Below C$100, the invoice needs the supplier's name, the date and the total. From C$100 you also need the supplier's GST/HST number and the tax charged (or a statement that it's included). From C$500 you also need your name, the payment terms and a description of what you bought. Check unfamiliar supplier numbers with our GST/HST number lookup guide.

From invoices to the return: calculating net tax

The GST/HST return turns all of this into one number. The core lines are:

Calculate net tax for a reporting period

1. 1

   Line 101 — total revenue

   Add all sales and other revenue for the period, including zero-rated and exempt sales, but excluding the GST/HST and PST you charged. Round to the nearest dollar.

2. 2

   Line 103 — GST/HST collected or collectible

   The tax on every taxable invoice in the period, at the rate of each sale's province — not just the tax you've been paid.

3. 3

   Line 106 / 108 — input tax credits

   Your ITCs for the period (line 106) plus any adjustments that reduce tax (line 107) give the total on line 108.

4. 4

   Line 109 — net tax

   Line 105 (tax collected plus increasing adjustments) minus line 108. A positive number is owed; a negative one is a refund.

5. 5

   Lines 110–115 — instalments and balance

   Subtract instalments and rebates to get the amount owing (line 115) or refund claimed (line 114).

Worked quarter — the Ottawa contractor. Taxable sales of C$42,000 to Ontario clients, so HST collected (line 103) = C$5,460. ITCs (line 108) = C$2,086.50. Net tax (line 109) = C$5,460 − C$2,086.50 = C$3,373.50 owing. Line 101 shows C$42,000.

Note that line 103 is tax "collected or collectible": if a client hasn't paid an invoice issued this quarter, the tax on it is still reported now. Tax on bad debts you later write off can be recovered through an adjustment on line 107.

When the quick method changes the maths

Small businesses with annual worldwide taxable sales of C$400,000 or less can elect the quick method. You still charge customers the normal rate and calculate each invoice exactly as above. The difference is the return: instead of tracking ITCs, you multiply your tax-included sales by a remittance rate — for example 8.8% for an Ontario service business — and take a 1% credit on the first C$30,000 of eligible sales.

For a consultant with C$90,000 of Ontario sales, tax-included sales are C$101,700. Quick method remittance before the credit = C$101,700 × 8.8%. Compare that with the HST collected (C$11,700) minus actual ITCs before electing; our quick method guide works through the comparison in full.

Common HST calculation mistakes

Taking a percentage of the total. 13% of a tax-included figure is always too high. Divide by 1.13.

Using your own province's rate. A Toronto business shipping to Edmonton charges 5%, not 13%. Rate by place of supply, not by your address.

Still charging 15% in Nova Scotia. Nova Scotia has been 14% since 1 April 2025. Update old price lists and plug-ins.

Taxing tax. GST on PST, or PST on GST, is wrong everywhere in Canada today.

Rounding every line. Calculate tax on each rate's subtotal and round once.

Claiming ITCs from receipts without a registration number. Above C$100, no number means no ITC if the CRA audits.

Official links

• CRA — GST/HST calculator and ratesOfficial rates by province
• CRA — RC4022 General Information for GST/HST RegistrantsRounding, invoices, ITCs
• CRA — Methods to calculate ITCsDetailed vs simplified method
• CRA — Instructions for preparing a GST/HST returnLine-by-line guide
• Revenu Québec — Calculating the taxesGST and QST calculation

What to do next

Put the right rates into your invoicing software, set it to round on subtotals, and use our Canada GST/HST calculator whenever you need to add or strip tax from a figure. If you haven't registered yet, read our GST registration guide to see when the C$30,000 test applies to you, and the GST/HST overview for filing deadlines.

This is general information, not legal or tax advice — confirm on the official source or with a professional.

Frequently asked questions

How do I calculate 13% HST on a price?

Multiply the pre-tax price by 0.13 to get the HST, or by 1.13 to get the total. A C$850 Ontario invoice carries C$110.50 HST, for a total of C$960.50. Use 14% (×0.14) in Nova Scotia and 15% (×0.15) in New Brunswick, Newfoundland and Labrador and PEI, and 5% (×0.05) in GST-only provinces.

How do I remove HST from a total?

Divide the tax-included total by 1 plus the rate. In Ontario, divide by 1.13: C$500 ÷ 1.13 = C$442.48 before tax, so the HST is C$57.52. A shortcut for the tax alone is total × 13/113. Don't multiply the total by 13% — that gives C$65.00, overstating the tax by C$7.48.

What is the reverse HST formula?

Pre-tax price = total ÷ (1 + rate). HST = total − pre-tax price, or total × rate ÷ (1 + rate). For Ontario that's 13/113 of the total, Nova Scotia 14/114, and New Brunswick, Newfoundland and Labrador and PEI 15/115. In a GST-only province, GST is 5/105 of the total.

How does the CRA want GST/HST rounded?

Round to the nearest cent: a fraction under half a cent may be rounded down, and half a cent or more is rounded up. When several items taxed at the same rate are on one sale, you may total them first, calculate the tax once and round once. Revenu Québec applies the same half-cent rule to the QST.

Do I charge GST on PST in BC, Saskatchewan or Manitoba?

No. The CRA tells businesses to calculate GST on the price without PST, and PST is calculated on the price without GST. On a C$400 taxable sale in BC you charge C$20 GST and C$28 PST, for C$448. Only the old pre-2013 Quebec system taxed one sales tax on top of another.

How do I calculate the GST/HST I can claim back?

Add up the GST/HST shown on your eligible business purchase invoices for the period — that total is your input tax credits. Small businesses that qualify for the simplified method can instead total their tax-included eligible purchases and multiply by the tax fraction, such as 13/113 in Ontario. Meals and entertainment are generally limited to 50% of the tax paid.

Sources & verification

Figures on this page were checked against the sources below when it was last reviewed on 11 October 2026. Each rate and limit is stored once with its own official source and review date, and official update channels are monitored daily so changes are picked up. How we verify

1. 1.GST/HST calculator (and rates) — Canada Revenue Agency · accessed 11 October 2026
2. 2.RC4022 General Information for GST/HST Registrants — Canada Revenue Agency · accessed 11 October 2026
3. 3.Calculate input tax credits – Methods to calculate the ITCs — Canada Revenue Agency · accessed 11 October 2026
4. 4.Instructions for preparing a GST/HST return — Canada Revenue Agency · accessed 11 October 2026
5. 5.Charge and collect the tax – Which rate to charge — Canada Revenue Agency · accessed 11 October 2026
6. 6.Calculating the Taxes (GST and QST) — Revenu Québec · accessed 11 October 2026
7. 7.GST/HST Registry information — TaxTips.ca · accessed 11 October 2026