How do I calculate reverse HST in Ontario?

Divide the total by 1.13 to get the price before HST, then subtract that from the total to get the HST. For example, $113 ÷ 1.13 = $100.00, so the HST is $13.00.

Why divide by 1.13 and not multiply by 0.13?

HST is charged on the pre-tax price, so multiplying the total by 13% overstates the tax. Dividing by 1.13 isolates the pre-tax price correctly.

Is HST 13% everywhere in Canada?

No. Ontario is 13%. New Brunswick, Newfoundland and Labrador and Prince Edward Island are 15%, and Nova Scotia is 14%. Use the province buttons above to switch.

Reverse HST Calculator — Ontario

Know the total but not the price before HST? Enter it below and back out Ontario's 13% HST.

Quick select province / territory

Province / territory

Amount before tax

Claim percentage

Before tax

$0.00

Tax

$0.00

Total

$0.00

GST/HST paid

$0.00

ITC you can claim

$0.00

Not recoverable

$0.00

Net cost to you

$0.00

Estimate only — ITCs depend on being GST/HST registered and on the purchase being for business use. Check with CRA or your accountant.

Province / territory	Rate	Tax	Total

Sorted lowest to highest combined rate. Green = lowest, red = highest, outlined = your selected province.

How to back out HST in Ontario

Ontario charges 13% HST (5% federal + 8% provincial) as a single tax. To remove it from a total, divide by 1.13.

Step 1: Divisor = 1 + 0.13 = 1.13.
Step 2: Pre-tax price = total ÷ 1.13. Example: $226 ÷ 1.13 = $200.00.
Step 3: HST = total − pre-tax price = $226 − $200 = $26.00.
Check: $200 × 1.13 = $226.00 ✓

The same method works in the other HST provinces — just change the rate: 15% in New Brunswick, Newfoundland & Labrador and PEI (divide by 1.15), and 14% in Nova Scotia (divide by 1.14). More on Ontario sales tax.

Frequently asked questions

How do I calculate reverse HST in Ontario?: Divide the total by 1.13 to get the price before HST, then subtract that from the total to get the HST. For example, $113 ÷ 1.13 = $100.00, so the HST is $13.00.
Why divide by 1.13 and not multiply by 0.13?: HST is charged on the pre-tax price, so multiplying the total by 13% overstates the tax. Dividing by 1.13 isolates the pre-tax price correctly.
Is HST 13% everywhere in Canada?: No. Ontario is 13%. New Brunswick, Newfoundland and Labrador and Prince Edward Island are 15%, and Nova Scotia is 14%. Use the province buttons above to switch.

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All-province calculator Reverse sales tax Reverse HST Ontario Reverse GST/QST Quebec Reverse GST/PST BC ITC calculator

Rates last checked: September 2026. Sources: Canada Revenue Agency (CRA) GST/HST rate schedule; provincial revenue agencies for PST/RST/QST rates.