Why “just add 5%” got me in trouble with a Toronto client
The first time I invoiced a client in Ontario, I made an assumption that cost me an awkward correction email. I knew Canada’s federal GST rate was 5%, so that’s what I quoted. Turns out Ontario doesn’t just charge the 5% federal GST — it uses HST, a blended rate that combines federal and provincial tax into one number, and in Ontario that’s 13%, not 5%.
My client politely pointed this out before I sent the actual invoice, which saved me from underbilling by 8 percentage points on a project that mattered. Since then I’ve learned that “Canadian tax” isn’t one number — it genuinely depends on which province you’re dealing with, and the differences aren’t small.
What GST/HST actually means
Canada runs a mixed system. Some provinces use HST (Harmonized Sales Tax), which folds the federal GST and the provincial sales tax into a single combined rate. Others charge GST and PST (Provincial Sales Tax) as two separate line items. And a couple, like Alberta, only charge the base 5% federal GST with no provincial sales tax layered on top at all.
Here’s roughly how it breaks down:
- HST provinces (Ontario, Nova Scotia, New Brunswick, Newfoundland & Labrador, Prince Edward Island): one blended rate, ranging from 13% to 15%.
- GST + PST provinces (British Columbia, Saskatchewan, Manitoba): 5% federal GST plus a separate provincial rate, usually landing the combined total between 11% and 12%.
- GST-only (Alberta): just the 5% federal rate, no provincial sales tax.
- Quebec runs its own system (GST + QST) that combines to roughly 14.975%.
Real example: Billing a client in Ontario C$1,000 for work. At 13% HST, that’s C$130 in tax, for a total of C$1,130. The exact same invoice to a client in Alberta would only carry C$50 in tax (5% GST), totaling C$1,050. Same job, same amount, genuinely different tax outcome depending on province.
How to use the calculator
- Enter your amount.
- Choose whether you’re adding tax to a net price or removing tax from a total.
- Select the correct province — this is the step people skip, and it’s the one that actually determines your rate.
- Read your breakdown: pre-tax price, tax amount (labeled with the specific rate and type), and the final total.
The mistake worth avoiding
Don’t assume a flat national rate for Canada. Unlike the UK or Australia, there isn’t one single number that applies everywhere — the province genuinely changes your math, sometimes by a large margin. Always check where your client or business is actually based before you calculate, not just what country they’re in.
Common questions
What’s the difference between GST and HST? GST is the federal 5% tax. HST is a blended rate some provinces use that combines the federal GST with a provincial sales tax into one number.
Which provinces have the highest combined rate? Nova Scotia, New Brunswick, Newfoundland & Labrador, and Prince Edward Island all sit at 15% HST — the highest in the country.
Do I charge my own province’s rate or my client’s? This depends on the type of good or service and specific place-of-supply rules the CRA sets out — it’s genuinely one of the more nuanced parts of Canadian sales tax, and worth confirming with an accountant if you’re regularly billing across provinces.
Frequently Asked Questions
What’s the difference between GST, HST, and PST? GST is the federal 5% tax that applies everywhere in Canada. HST is a blended rate some provinces use that combines GST with a provincial component into one number. PST is a separate provincial sales tax charged on top of GST in provinces that don’t use HST.
Which provinces use HST? Ontario, Nova Scotia, New Brunswick, Newfoundland & Labrador, and Prince Edward Island all use HST, with combined rates ranging from 13% to 15%.
Does every province charge the same total tax rate? No — this is the biggest thing to get right. Alberta charges only the 5% federal GST with no provincial layer. Other provinces combine GST with PST separately, landing around 11–12% combined. Quebec runs its own GST+QST system at roughly 14.975%. Always check the specific province before calculating.
Do I charge my province’s tax rate or my client’s? This depends on “place of supply” rules the CRA sets, which vary by the type of good or service involved. It’s one of the more nuanced parts of Canadian sales tax — worth confirming with the CRA’s guidance or an accountant if you regularly bill clients in other provinces.
Is GST/HST the same as sales tax in the US? They serve a similar purpose but work differently. GST/HST is collected at multiple stages of a supply chain (value-added style), while US sales tax is typically charged once, at the final point of sale to the consumer.