GST Calculator

What Is GST and How Does This Calculator Work?

The Goods and Services Tax (GST) is Canada’s federal value-added tax. It has been 5% since 2008 and applies to most goods and services in every province and territory. This GST calculator handles the GST-only jurisdictions — Alberta, British Columbia, Saskatchewan, Manitoba, Yukon, Northwest Territories, and Nunavut — letting you compute the 5% GST on any pre-tax amount or back it out of a tax-included total. In BC, Saskatchewan, and Manitoba, PST still applies separately; for the full combined rate, use our GST/PST calculator.

Toggle between “Add Tax to Price” and “Remove Tax from Total” depending on whether you have the subtotal or the receipt total. The 5% rate is editable in case future federal rate changes or special rebate scenarios require a custom number. The calculation uses Canadian dollar formatting and shows the full breakdown so you can confirm the tax math at a glance.

GST Rates by Province and Territory (2025)

GST is a single national rate, but the combined sales tax differs by province because PST, QST, and HST stack on top. The provinces and territories where this calculator’s 5% GST is the dominant sales tax:

• Alberta: 5% GST only — no provincial sales tax
• Yukon: 5% GST only
• Northwest Territories: 5% GST only
• Nunavut: 5% GST only
• British Columbia: 5% GST + 7% PST = 12% combined
• Saskatchewan: 5% GST + 6% PST = 11% combined
• Manitoba: 5% GST + 7% RST = 12% combined

HST provinces (Ontario, Nova Scotia, New Brunswick, PEI, Newfoundland and Labrador) and Quebec (which uses GST+QST) follow different rules — use the HST calculator or Quebec sales tax calculator for those.

GST Formulas: Forward and Reverse

• GST amount = Subtotal × 0.05
• Total = Subtotal × 1.05
• Subtotal (from total) = Total ÷ 1.05
• GST (from total) = Total − Subtotal

Example for Alberta or any territory: a $250 pre-tax purchase → GST = $12.50, total = $262.50. Reverse a $262.50 receipt ÷ 1.05 = $250.00 pre-tax and $12.50 GST. The same formula works at any rate — just change the multiplier. If the federal government ever changes the GST rate, edit the rate field in the calculator above and the math stays correct.

Zero-Rated, Exempt, and Taxable Supplies

Not everything is taxed at 5%. Canada’s GST system distinguishes three categories:

• Taxable (5%): most goods and services — clothing, electronics, restaurant meals, professional services, alcohol, fuel, vehicle purchases.
• Zero-rated (0%): basic groceries, prescription drugs, medical devices, exports, most agricultural products. Tax is technically charged at 0%, so registrants can still claim ITCs on related inputs.
• Exempt (no GST): residential rent, most health and dental services, child care, educational services, most financial services. No GST is collected and no ITCs are claimable for related expenses.

The distinction between zero-rated and exempt matters most for business inputs: zero-rated suppliers can recover GST paid on their costs; exempt suppliers cannot. This is why most basic groceries are zero-rated rather than exempt — it lets supermarkets reclaim GST on the equipment and supplies needed to sell them.

GST Registration and Quick Method

Businesses must register for GST/HST once worldwide taxable revenue exceeds $30,000 in a single calendar quarter or across four consecutive quarters. Once registered, you collect GST from customers, claim Input Tax Credits for GST paid on business inputs, and remit the difference. Below the $30,000 threshold registration is optional — voluntary registrants can claim ITCs from day one but must charge GST on all taxable sales.

The CRA’s Quick Method election simplifies remittance for many small businesses. Instead of tracking every ITC, you remit a flat percentage of GST-included revenue (around 3.6% for service businesses in Alberta) and keep the difference. It usually benefits businesses with low input costs — consultants, freelancers, and most personal-service providers. Pair this calculator with our markup calculator when setting prices and our profit percentage calculator when reviewing margins.

Common GST Mistakes to Avoid

• Charging GST in HST provinces. If you ship to Ontario from Alberta, charge 13% HST — not 5% GST. Place-of-supply rules tie the rate to the customer’s province.
• Forgetting PST in BC, SK, MB. A 5% GST quote in those provinces misses the 6%–7% PST that also applies on most sales.
• Multiplying the total by 5% to back out GST. $105 × 0.05 = $5.25; the correct answer is $5.00. Always divide by 1.05.
• Missing the small-supplier transition. The day you cross $30,000 in any single quarter you must charge GST on that sale forward — not at the start of the next quarter.
• Skipping ITC documentation. Without a supplier’s GST number on receipts over $30, the CRA can deny the input tax credit on audit.

Disclaimer

This calculator is for informational purposes only. GST rates and rules can change; verify current rates with the Canada Revenue Agency before relying on a calculation for a business filing or contract. Consult a Canadian tax professional for guidance on registration, ITCs, place-of-supply, or any specific GST issue.