How to Deduct HST From a Total Price (Step-by-Step with Formula)

You just received an invoice for $1,130. You know there is 13% HST buried in that number, but your accounting software needs the "pre-tax" amount. You could guess, but if you are out by even a few cents, your tax return won't balance.

Searching for "how to remove HST" usually lands you in a swamp of academic tax jargon or confusing spreadsheets. You don't need a degree in accounting; you just need one simple calculation that works every time. This guide gives you that formula and shows you exactly how to use it.

Why You Actually Need to "Back Out" HST

If you are a business owner in Canada, you aren't just paying HST; you are collecting it for the government. To get that money back through Input Tax Credits (ITCs), you must separate the tax from the base cost for every single receipt.

You might also need this to check if a vendor overcharged you. Mistakes happen, and sometimes a 13% tax is accidentally applied to a total that already included tax. Finally, if you are splitting a bill with a friend who can claim HST back, you need to know the exact breakdown to be fair.

The Formula Explained (Step-by-Step)

The math is simpler than it looks. You aren't "subtracting" 13%, because 13% of the total is more than 13% of the original price. You are dividing to find the starting point.

1. Identify your rate: Find the tax rate for your province (e.g., Ontario is 13%).
2. Create your divisor: Add 1 to the decimal version of that rate. For 13%, use 1.13. For 15%, use 1.15.
3. Divide the total: Take your final receipt amount and divide it by that number.

2026 Province Rate & Divisor Table

Rates vary across the country. Use this table to find the exact number you need to divide by based on where the purchase happened.

Province	Tax Type	Rate	Divisor to Use
Ontario	HST	13%	1.13
Nova Scotia, NB, NL, PEI	HST	15%	1.15
BC, Manitoba	GST + PST	12%	1.12
Quebec	GST + QST	14.975%	1.14975
Saskatchewan	GST + PST	11%	1.11
Alberta, Yukon, NWT, Nunavut	GST Only	5%	1.05

Three Worked Examples With Real Numbers

Example 1: The Ontario Freelancer

You are an Ontario freelancer and you just invoiced a client for a flat fee of $2,260. You need to know your actual earnings before the government takes their cut.

Total: $2,260. Rate: 13%. Divisor: 1.13.

Calculation: $2,260 ÷ 1.13 = $2,000.00. Your fee was $2,000, and the HST you collected was $260.

Example 2: The BC Laptop Purchase

You bought a high-end laptop in Vancouver for a total of $1,344. You need the base price for your company's asset register.

Total: $1,344. Rate: 12% (5% GST + 7% PST). Divisor: 1.12.

Calculation: $1,344 ÷ 1.12 = $1,200.00. The laptop cost $1,200 before $144 in tax was added.

Example 3: The Nova Scotia Contractor

A contractor in Halifax quotes you $4,025 for a project, tax included. You need to isolate the tax portion to see if it fits your budget.

Total: $4,025. Rate: 15%. Divisor: 1.15.

Calculation: $4,025 ÷ 1.15 = $3,500.00. The base work is $3,500, and $525 is HST.

Common Mistakes to Avoid

The biggest error people make is "subtracting 13%." If you take $1,130 and multiply it by 0.13, you get $146.90. If you subtract that, you get $983.10.

That is wrong. You have just lost $16.90 of your own money because you calculated tax on the tax. Always divide by 1.13 instead of multiplying by 0.87.

Also, ensure you are using the rate for the province where the seller is located, not where you live. If you buy software from a company in Alberta, you only pay 5% GST, even if you are sitting in Toronto.

Frequently Asked Questions

Is HST the same across all of Canada?

No. HST only exists in five provinces (Ontario, NB, NS, NL, and PEI). Other provinces use a combination of federal GST (5%) and provincial PST, or GST only.

How do I calculate the HST amount separately?

Once you have the pre-tax price using our formula, simply subtract it from your total. Total ($1,130) minus Pre-Tax ($1,000) equals your HST ($130).

Can I claim the HST back if I'm a business?

Yes, provided you are HST-registered with the CRA. These are called Input Tax Credits (ITCs) and they directly reduce the amount of tax you owe the government.

What's the difference between GST and HST?

GST is the 5% federal tax. HST (Harmonized Sales Tax) is just the federal GST and provincial tax blended into one single 13% or 15% payment.

What if my invoice shows GST and PST separately?

You can still use the formula. Just add the two rates together. If GST is 5% and PST is 7%, your total rate is 12%. Divide your total by 1.12.

Stop guessing and start calculating. Take one real invoice sitting in your inbox right now and apply this formula to find the base price. Or, if you have a stack of receipts to process, bookmark our free HST removal tool to get through them in half the time.