About TaxMapCA
What it is, how it works, and what it is not.
Overview
What is TaxMapCA?
TaxMapCA is a sales tax decision engine for Canadian businesses. It answers the question every small business eventually faces: "What tax do I actually charge this customer?"
The answer depends on more than just your province. It depends on where your customer is located, what you are selling, and whether you are registered for GST/HST and applicable provincial taxes. Getting it wrong means either undercharging (and owing the difference to the CRA out of pocket) or overcharging (and creating refund headaches).
TaxMapCA takes those variables, runs them through a rules engine built on official government publications, and returns the correct rate with a plain-English explanation and a direct link to the source it used.
Under the hood
How it works
The core is a pure TypeScript rules engine — no AI, no guessing. Every rate, every exemption, and every place-of-supply rule is stored as versioned data with three required fields:
Source URL: A direct link to the government page the rule came from — CRA, Revenu Québec, or a provincial tax authority.
Effective date: When the rule or rate became active. Historical rates are kept so the engine can be audited.
Plain-English description: What the rule covers, in human language, so results can be explained to users rather than just asserted.
When a rate changes (which happens — Quebec's QST rate changed in 2013, for example), we update the data file with the new rate and effective date. No logic changes, no regression risk. The engine reads the data and applies it.
Primary government sources
- GST/HST for businesses
Canada Revenue Agency
- Place of supply rules
Canada Revenue Agency
- QST overview
Revenu Québec
- Provincial Sales Tax (BC PST)
BC Ministry of Finance
- Provincial Sales Tax (SK PST)
Saskatchewan Finance
- Retail Sales Tax (MB RST)
Manitoba Finance
The builder
Who made this
TaxMapCA was built by Uday Parmar (Accidental-MVP) to solve a problem that comes up constantly when running a Canadian small business: figuring out the right tax to charge without spending an hour on the CRA website.
The CRA's own documentation is comprehensive but written for accountants and lawyers. The goal here was to build something that gives a small business owner the correct answer in under 60 seconds, with the government source attached so they can verify it themselves.
Important limits
What this is NOT
Not legal or tax advice
TaxMapCA provides tax information, not advice. There is a meaningful difference. A tool can tell you the rate — a qualified tax professional can tell you whether it applies to your specific situation, how it interacts with your accounting method, and what to do if you have made past errors.
Not affiliated with the CRA or any government
TaxMapCA is an independent tool. It is not endorsed by, affiliated with, or approved by the Canada Revenue Agency, Revenu Québec, or any provincial tax authority. Always verify critical decisions against the official sources linked in each result.
Not a substitute for a tax professional
Edge cases exist. First Nations exemptions, non-resident sellers, financial services, charities, digital platforms, and mixed-use supplies can all behave differently from the general rules. If your situation is complicated, talk to a CPA or tax lawyer.
Not guaranteed to be current at the moment you read it
Tax rates and rules change. We update the engine when changes are announced, but there may be a lag. Every result shows the effective date of the rates used. If you are making a material business decision, verify the rate directly with the source URL provided.