Ontario HST Reverse Calculator
Calculate the estimated pre-tax price and included HST amount for Ontario tax-inclusive totals.
Interactive calculator
Calculate tax backwards
$100.00 at 13% Ontario HST: pre-tax $88.50, Ontario HST $11.50.
Estimate only. Verify official rates before filing, invoicing, or making tax decisions.
Primary query
ontario hst reverse calculator
Default rate
13%
Rate source
Ontario Ministry of Finance HST ratesLast updated
2026-05-14
Formula
How reverse tax calculation works
Start with the tax-inclusive total, then divide by 1 plus the tax rate. Use the tax rate as a decimal in the formula.
Pre-tax Price = Total Price / (1 + Tax Rate)
Tax Amount = Total Price - Pre-tax Price
Example
$100.00 CAD with 13% HST
- Tax multiplier = 1.13
- Pre-tax price = 100 / 1.13 = 88.50
- Estimated HST amount = 11.50
Region
Ontario tax context
Country
Canada
Tax system
HST
Reference rate
13%
Ontario uses harmonized sales tax for many goods and services. Always verify the rate for the exact product, location, and filing period before making tax decisions.
Rate breakdown
Estimated split for $100.00.
- Federal part5% reference rate
- 5% / $4.42
- Ontario provincial part8% reference rate
- 8% / $7.08
Source checked 2026-05-14: Ontario Ministry of Finance HST rates. Ontario HST is 13%, consisting of a 5% federal part and an 8% provincial part.
FAQ
ontario hst reverse calculator questions
How do you reverse calculate tax?
Divide the tax-inclusive total by 1 plus the tax rate. For example, with a 20% tax rate, divide the total by 1.20.
What is the reverse tax formula?
Pre-tax price = total price / (1 + tax rate). Tax amount = total price - pre-tax price.
Is this calculator tax advice?
No. This is an educational calculator for estimates. Confirm official rates and rules before filing, invoicing, or making compliance decisions.
What Ontario HST rate does this page use?
It defaults to 13% as the Ontario HST reference rate for estimates.
Is Ontario HST calculated differently from GST plus QST?
The reverse formula is the same, but Ontario uses one harmonized 13% HST rate. Quebec commonly combines separate GST and QST components.
How do I remove 13% HST from an Ontario total?
Divide the HST-inclusive total by 1.13. Then subtract the net price from the total to estimate the included HST amount.
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