How to Calculate GST from Total Amount in Canada (2025 Guide)
In Canada, the Goods and Services Tax (GST) is a federally imposed value-added tax applied to most goods and services sold or consumed. Depending on the province, it may be combined with provincial taxes to form the Harmonized Sales Tax (HST). This guide walks you through how to calculate GST or HST from a total amount, including formulas, examples, and tools like the GST/HST Calculator.
What is GST?
The GST is a 5% federal tax that applies to the majority of goods and services sold in Canada. Some provinces apply their own sales tax, leading to HST—a combination of GST and provincial sales tax.
GST and HST Rates by Province (2025)
| Province/Territory | GST | HST | Total Rate |
|---|---|---|---|
| Alberta | 5% | — | 5% |
| British Columbia | 5% | — | 5% + 7% PST |
| Ontario | — | 13% | 13% HST |
| Nova Scotia | — | 15% | 15% HST |
| Newfoundland and Labrador | — | 15% | 15% HST |
| Manitoba | 5% | — | 5% + 7% RST |
| Quebec | 5% | — | 5% + 9.975% QST |
When is GST Included in the Price?
In some cases, the total amount you see already includes GST or HST. Businesses are required to state whether their prices are inclusive of tax. If you’re unsure, you can back-calculate the GST using a simple formula.
Formula: How to Calculate GST from Total Amount
For 5% GST:
GST = Total × (5 / 105)
For 13% HST (Ontario):
HST = Total × (13 / 113)
For 15% HST (Nova Scotia):
HST = Total × (15 / 115)
Example 1: GST Only (Alberta)
You purchased an item that costs CAD $210 (inclusive of 5% GST).
Net Price = $200
Example 2: HST (Ontario – 13%)
Total paid: CAD $226
Base Price = $200
Example 3: HST (Nova Scotia – 15%)
Total paid: CAD $230
Net Price = $200
GST-Inclusive vs GST-Exclusive
- GST-Inclusive: Price already includes GST/HST
- GST-Exclusive: GST/HST will be added on top
GST Calculation for Businesses
If you’re a GST/HST-registered business, you must:
- Charge GST/HST on taxable sales
- Remit collected tax to the CRA
- Claim Input Tax Credits (ITCs) for GST paid on business purchases
How to Remit GST/HST to CRA
Use CRA’s online portal or paper filing. File monthly, quarterly, or annually based on your revenue. Keep proper invoices showing tax details.
Use the GST/HST Calculator
Want fast, accurate GST breakdowns? Use our free GST/HST Calculator. It allows you to:
- Calculate tax inclusive and exclusive amounts
- Choose province-specific tax rates
- Get breakdowns for invoicing or receipts
GST Refunds and Input Tax Credits
Businesses can claim GST paid on business purchases as input tax credits (ITCs). Individuals may qualify for GST/HST rebates or credits through CRA depending on income.
How to Handle GST on Imports
Importing into Canada? GST is typically applied at the border. You can calculate estimated duties and GST with our Import Duty Calculator.
GST Exempt and Zero-Rated Items
- Zero-rated: Basic groceries, prescription drugs, exports (taxed at 0%)
- Exempt: Residential rent, health, education services (not taxed, no ITCs)
FAQ: GST from Total Amount
How do I reverse-calculate GST?
Use the formula: GST = Total × (5 / 105). Replace 5 with 13 or 15 for HST.
Do prices in Canada include GST?
Usually not—GST is added at checkout unless otherwise stated.
How much GST do I pay on a $500 item?
- At 5%: $25
- At 13%: $65
- At 15%: $75
Key Takeaways
- GST in Canada is 5%, but may be higher when combined as HST
- Use reverse formulas to extract GST from a total
- GST/HST Calculator simplifies all calculations
- Imports also attract GST—use the Import Duty Calculator to plan costs
Conclusion
Calculating GST from the total amount in Canada is easy when you know the rate and use the right formula. Whether you’re in Alberta (5% GST) or Nova Scotia (15% HST), reverse-calculating the tax is essential for budgeting, business reporting, and invoicing. Save time using tools like the GST/HST Calculator and stay compliant with Canadian tax laws.