An HST calculator adds harmonized sales tax to a pre-tax price, or works backwards from a tax-included total to the amount before tax. In Ontario the HST is 13%, so a $10,000 job is $11,300 with tax ($10,000 × 1.13), and a $11,300 receipt was $10,000 before tax ($11,300 ÷ 1.13).
Open the free HST calculator in your browser. No login, no email, nothing to pay.
Open the free toolContruva’s free HST calculator does both directions for every province and territory, including the GST-plus-PST provinces and Quebec’s GST plus QST. It shows each tax on its own line, the combined rate, and a table of the same amount in all 13 provinces and territories. No login and no email.
How to use the HST calculator
“Add tax” starts from a price before tax. “Remove tax (reverse)” starts from a total that already includes tax.
A quote subtotal, a supplier invoice total, a receipt, anything in dollars.
The list shows each rate, such as Ontario 13% HST or Quebec 5% GST + 9.975% QST. There’s also a custom rate for US jobs and a no-tax option.
You get the amount before tax, each tax line, the total tax, the total with tax, and the formula with your numbers in it.
Under the result is a comparison table that runs your amount through every province. It’s handy when you work near a border, buy from out-of-province suppliers, or just want to see what a job would cost a customer in Halifax compared to Toronto.
How to calculate HST
HST is a percentage of the pre-tax price. Turn the rate into a decimal, multiply, and add it on. The shortcut is to multiply by one plus the rate in a single step.
| You want | Formula | Ontario example (13%) |
|---|---|---|
| HST on a price | HST = price × rate | $10,000 × 0.13 = $1,300 |
| Total with HST | Total = price × (1 + rate) | $10,000 × 1.13 = $11,300 |
| Price before HST | Pre-tax = total ÷ (1 + rate) | $11,300 ÷ 1.13 = $10,000 |
| HST inside a total | HST = total − (total ÷ (1 + rate)) | $11,300 − $10,000 = $1,300 |
In provinces with two taxes, each one is charged on the same pre-tax price. They aren’t stacked: Quebec’s QST is not charged on the GST. So $1,000 in Quebec is $50.00 GST plus $99.75 QST, for $1,149.75. The calculator handles that for you and shows both lines.
Reverse HST: taking tax out of a total
The reverse HST calculation is the one people get wrong. You can’t take 13% off a tax-included total, because the 13% was calculated on the smaller, pre-tax number. Divide by 1.13 instead.
$5,000 tax-included ÷ 1.13 = $4,424.78 before tax, and $575.22 of HST.
Taking 13% off $5,000 would give you $4,350, which is $74.78 too low. On a supplier invoice, that’s the wrong number in your books. On a customer who says “I’ve got $5,000 all in,” it means you quote a smaller job than they can actually afford.
Contractors use the reverse calculation all the time:
- Receipts and supplier invoices that only show a total, so you can book the cost and the HST separately.
- “All-in” budgets from customers, so you know the pre-tax scope you can quote.
- Checking a competitor’s price or an old quote where only the total survived.
- Splitting a deposit or progress payment into the part that’s revenue and the part that’s tax you owe.
When the calculator works backwards it rounds the pre-tax amount to the cent and gives any leftover cent to the last tax line, so the pre-tax amount plus the tax always equals the total you typed in.
HST calculator for Ontario
Ontario charges a single 13% HST: 5% federal and 8% provincial, collected together as one tax. It’s the default in the calculator. A few quick Ontario numbers:
| Before HST | HST (13%) | Total |
|---|---|---|
| $1,000.00 | $130.00 | $1,130.00 |
| $4,424.78 | $575.22 | $5,000.00 |
| $10,000.00 | $1,300.00 | $11,300.00 |
| $25,000.00 | $3,250.00 | $28,250.00 |
The other HST provinces work the same way with a different multiplier: 1.14 in Nova Scotia and 1.15 in New Brunswick, Newfoundland and Labrador, and Prince Edward Island.
HST, GST and PST rates by province in 2026
These are the general rates the calculator uses. The GST/HST column matches the CRA’s GST/HST rate table, which shows Nova Scotia’s HST falling from 15% to 14% on April 1, 2025 (checked November 2026). PST, RST and QST are set by each province. The totals are for a $10,000 pre-tax price.
| Province or territory | Tax | Combined | Total on $10,000 |
|---|---|---|---|
| Ontario | 13% HST | 13% | $11,300.00 |
| Nova Scotia | 14% HST | 14% | $11,400.00 |
| New Brunswick | 15% HST | 15% | $11,500.00 |
| Newfoundland and Labrador | 15% HST | 15% | $11,500.00 |
| Prince Edward Island | 15% HST | 15% | $11,500.00 |
| Quebec | 5% GST + 9.975% QST | 14.975% | $11,497.50 |
| British Columbia | 5% GST + 7% PST | 12% | $11,200.00 |
| Manitoba | 5% GST + 7% RST | 12% | $11,200.00 |
| Saskatchewan | 5% GST + 6% PST | 11% | $11,100.00 |
| Alberta, Yukon, NWT, Nunavut | 5% GST | 5% | $10,500.00 |
And in reverse, here’s what a $11,300 tax-included total was before tax in a few provinces: $10,000.00 in Ontario, $9,912.28 in Nova Scotia, $9,826.09 in New Brunswick, $9,828.22 in Quebec, $10,089.29 in British Columbia, $10,180.18 in Saskatchewan and $10,761.90 in Alberta.
Quoting jobs with HST
Price the job first, then add tax. Your markup and margin are worked out on the pre-tax price, because HST is money you collect for the government, not revenue. The contractor markup calculator gets you to the pre-tax price; this calculator takes it from there.
- Show tax on its own line. Subtotal, HST (13%), total. Customers compare quotes, and a tax-included number with no breakdown looks higher than a competitor’s subtotal.
- Put your GST/HST number on the quote and invoice once you’re registered. Commercial customers need it to claim their own input tax credits.
- Tax the deposit too. A deposit that’s a down payment on the price is normally taxed like the rest of the price, so a 30% deposit on $10,000 in Ontario is $3,000 plus $390 HST.
- Know the PST rules for materials. In BC, Saskatchewan and Manitoba the provincial tax on construction work depends on the type of job. On many real property contracts the contractor pays PST on materials instead of charging it to the customer, and that PST belongs in your cost. See do contractors charge HST on materials.
If you want the quote itself done in a few minutes, the free contractor estimate generator adds tax by province and gives you a PDF.
When does a contractor have to register for HST?
You must register for a GST/HST account once you stop being a “small supplier.” Under the CRA’s rules you’re a small supplier while your taxable revenue, including any associated businesses, is $30,000 or less in a single calendar quarter and over the last four consecutive calendar quarters. Gross revenue counts, not profit.
You stop being a small supplier on the sale that takes you over, and you charge HST on that sale.
You stop being a small supplier at the end of the month after the quarter you went over in.
Many new contractors register voluntarily so they can claim back the HST they pay on tools, materials and the truck.
Once you’re registered, you charge HST on taxable work, file returns on schedule and remit what you collected minus what you can claim back. This is general information, not tax advice. Check the CRA’s GST/HST for businesses pages or talk to your accountant about your own situation.
Input tax credits: getting back the HST you pay
Registered contractors can usually claim input tax credits (ITCs) for the GST/HST they pay on purchases used to earn taxable revenue: materials, tools, fuel, equipment rentals, subcontractor invoices, software. You remit the HST you collected minus your ITCs.
You collect $1,300 HST on an $11,300 Ontario job. You paid $575.22 HST on $5,000 of materials for it. You remit $1,300 − $575.22 = $724.78 for that job.
That’s why the reverse calculation matters. Every supplier receipt you book as one lump total hides an ITC you could have claimed. Keep receipts that show the supplier’s GST/HST number, and split tax out when you record them.
HST mistakes that cost contractors money
| Mistake | What happens | The fix |
|---|---|---|
| Taking 13% off a total to “remove” HST | Pre-tax figure is too low | Divide by 1.13 |
| Quoting tax-included without saying so | Customer adds tax again, or thinks you’re pricier | Subtotal, tax and total on separate lines |
| Marking up the tax-included price | You add markup to the government’s money | Mark up first, add tax last |
| Not watching the $30,000 threshold | Tax owed on sales you didn’t charge it on | Track revenue by quarter |
| Booking receipts as one total | ITCs left unclaimed | Split tax out with the reverse calculation |
| Using last year’s rate | Wrong tax on the invoice (Nova Scotia changed in 2025) | Let your software hold the current rate |
Tax is also part of what an employee costs you, through CPP and EI. For that side of the numbers, see the labour burden calculator.
The right tax on every quote and invoice
The calculator is free and stays free. When you’re sending quotes every day, though, you shouldn’t be adding tax by hand. In Contruva your quoting software adds GST, HST, PST or QST on its own lines, and the customer signs on their phone and pays the deposit. The signed quote becomes the invoice, with card payments and automatic reminders.
It’s all one plan, Contruva Pro, at $249.99 CAD a month. Start a 7-day free trial, no credit card needed.