iBill.ca
Get Started
Complete 2026 Guide

How to Calculate GST on a Canadian Invoice — Formulas + Calculator

Everything you need to know about calculating GST, HST, and PST on invoices in Canada. Step-by-step formulas, provincial rates, and real examples.

5 Steps to Calculate GST on Any Invoice

Follow this simple process for accurate tax calculations every time

1

Find Customer Location

Tax rate depends on where your customer is located, not where you are.

2

Look Up Tax Rate

Check the rate table: HST (13-15%), GST only (5%), or GST+PST.

3

Calculate Subtotal

Add up all your line items (services, products, hours) before tax.

4

Apply Formula

Multiply subtotal by tax rate. For Quebec, both GST and QST are calculated on the subtotal.

5

Add to Invoice

Show tax separately on invoice. Add to subtotal for final total.

Quick Reference: 2026 Canadian Tax Rates by Province

Ontario
13%
HST
Nova Scotia
14%
HST
Alberta
5%
GST Only
British Columbia
12%
GST + PST
Quebec
14.975%
GST + QST
Saskatchewan
11%
GST + PST

Complete 2026 Canadian Sales Tax Rates

The tax you charge on invoices depends on where your customer is located. Here's every province and territory:

Province/Territory GST PST/HST Total Tax Type
Alberta5%0%5%GST only
British Columbia5%7%12%GST + PST
Manitoba5%7%12%GST + PST
New Brunswick15%15%HST
Newfoundland & Labrador15%15%HST
Northwest Territories5%0%5%GST only
Nova Scotia14%14%HST
Nunavut5%0%5%GST only
Ontario13%13%HST
Prince Edward Island15%15%HST
Quebec5%9.975%*14.975%GST + QST
Saskatchewan5%6%11%GST + PST
Yukon5%0%5%GST only

Important: Quebec QST Calculation

Since 2013, Quebec's QST (9.975%) is calculated on the subtotal only, the same base as GST. Both taxes are applied separately to the subtotal. The combined effective rate is 14.975%. See the Quebec example below.

How to Calculate GST (5% Provinces)

For provinces with GST only (Alberta, NWT, Nunavut, Yukon), the calculation is straightforward:

GST Formula

GST Amount = Subtotal × 0.05 Total = Subtotal + GST Amount

Example: Invoice to Alberta Customer

Consulting services: $1,500.00

Subtotal: $1,500.00
GST (5%): $1,500.00 × 0.05 = $75.00
Invoice Total: $1,575.00

How to Calculate HST (Combined Tax Provinces)

HST provinces combine federal GST and provincial tax into one rate. Use a single calculation:

HST Formula

HST Amount = Subtotal × HST Rate Total = Subtotal + HST Amount

Example: Invoice to Ontario Customer (13% HST)

Web design services: $2,000.00

Subtotal: $2,000.00
HST (13%): $2,000.00 × 0.13 = $260.00
Invoice Total: $2,260.00

Example: Invoice to Nova Scotia Customer (14% HST)

Photography services: $800.00

Subtotal: $800.00
HST (14%): $800.00 × 0.14 = $112.00
Invoice Total: $912.00

How to Calculate GST + PST (BC, Manitoba, Saskatchewan)

These provinces charge GST and PST separately. Both are calculated on the subtotal:

GST + PST Formula

GST Amount = Subtotal × 0.05 PST Amount = Subtotal × PST Rate Total = Subtotal + GST + PST

Example: Invoice to BC Customer (5% GST + 7% PST)

Marketing services: $3,000.00

Subtotal: $3,000.00
GST (5%): $3,000.00 × 0.05 = $150.00
PST (7%): $3,000.00 × 0.07 = $210.00
Invoice Total: $3,360.00

How to Calculate GST + QST (Quebec) - Special Rules

Quebec is unique: GST and QST are both charged separately, each calculated on the subtotal. The combined effective rate is 14.975% (5% + 9.975%).

Quebec GST + QST Formula

GST Amount = Subtotal × 0.05 QST Amount = Subtotal × 0.09975 Total = Subtotal + GST + QST

Example: Invoice to Quebec Customer

Graphic design services: $1,000.00

Subtotal: $1,000.00
GST (5%): $1,000.00 × 0.05 = $50.00
QST (9.975%): $1,000.00 × 0.09975 = $99.75
Invoice Total: $1,149.75

Common Quebec Mistake

Don't use the outdated pre-2013 compound formula! Since 2013, QST is calculated on the subtotal only, not on (Subtotal + GST). Using the old compound method would give you $104.74 instead of the correct $99.75 - overcharging by $4.99 on a $1,000 invoice.

How to Calculate GST From Total (Reverse Calculation)

Sometimes you need to work backwards - you know the total amount including tax and need to find the original subtotal and tax amount. This is called a "reverse" or "back" calculation.

Reverse GST Formula (5%)

Subtotal = Total ÷ 1.05 GST Amount = Total - Subtotal

Example: Finding GST from a $525 Total

You paid $525 total (including 5% GST). What was the subtotal and GST?

Total: $525.00
Subtotal: $525.00 ÷ 1.05 = $500.00
GST Amount: $525.00 - $500.00 = $25.00

Reverse Calculation for All Tax Rates

Province/Rate Divide By Example ($1,000 total)
Alberta, Territories (5% GST)1.05$952.38 subtotal + $47.62 GST
Saskatchewan (11% GST+PST)1.11$900.90 subtotal + $99.10 tax
BC, Manitoba (12% GST+PST)1.12$892.86 subtotal + $107.14 tax
Ontario (13% HST)1.13$884.96 subtotal + $115.04 HST
New Brunswick, NL, PEI (15% HST)1.15$869.57 subtotal + $130.43 HST
Nova Scotia (14% HST)1.14$877.19 subtotal + $122.81 HST
Quebec (14.975% GST+QST)1.14975$869.78 subtotal + $130.22 tax

Common GST Calculation Mistakes to Avoid

Wrong Province Rate

Using YOUR province's rate instead of your CUSTOMER'S province. Tax is based on where the customer is located (place of supply), not where you are.

Quebec QST Error

Using the outdated pre-2013 compound formula. Since 2013, Quebec QST is calculated on the subtotal only, not on (Subtotal + GST). Using the old formula overcharges by ~$5 per $1,000.

Rounding Errors

Rounding mid-calculation instead of at the end. Calculate the full tax amount first, then round to 2 decimal places for the final invoice.

Tax on Tax-Exempt Items

Charging GST/HST on exempt items like basic groceries, prescription drugs, or certain medical services. Know what's taxable in your industry.

Charging Without Registration

Charging GST/HST without being registered. You cannot charge and collect tax unless you have a GST/HST number from CRA.

Not Showing Tax Separately

CRA requires tax amounts to be shown separately on invoices. Don't just include tax in the price - break it out on a separate line.

Do I Need to Charge GST/HST?

Small Supplier Threshold

You don't need to register for or charge GST/HST if:

When You Must Register

You must register for GST/HST within 29 days if:

Voluntary Registration

Even if under $30,000, you may want to register voluntarily to:

What Must Appear on a CRA-Ready Invoice?

For invoices over $30, the CRA requires:

For invoices over $150, you also need:

Skip the Math - Let iBill Calculate Automatically

iBill.ca automatically calculates GST, HST, PST, and QST based on your customer's province. No more manual calculations or formula lookups.

Create Free Invoice

GST Calculation Examples by Industry

Here's how GST/HST calculation works for common industries and professions:

Freelance Designer (Ontario)

Logo Design Project

Services: Logo design, brand guidelines, business card design

Logo design (15 hrs × $85/hr): $1,275.00
Brand guidelines: $500.00
Business cards: $225.00
Subtotal: $2,000.00
HST (13%): $2,000.00 × 0.13 = $260.00
Invoice Total: $2,260.00

IT Consultant (Alberta)

Monthly Retainer Invoice

Services: IT support and consulting

Monthly retainer: $3,500.00
Additional support (8 hrs × $125/hr): $1,000.00
Software licenses (pass-through): $250.00
Subtotal: $4,750.00
GST (5%): $4,750.00 × 0.05 = $237.50
Invoice Total: $4,987.50

Contractor (British Columbia)

Home Renovation Invoice

Services: Kitchen renovation labour and materials

Labour (40 hrs × $65/hr): $2,600.00
Materials: $1,800.00
Subtotal: $4,400.00
GST (5%): $4,400.00 × 0.05 = $220.00
PST (7%): $4,400.00 × 0.07 = $308.00
Invoice Total: $4,928.00

Marketing Agency (Quebec)

Social Media Campaign

Services: Social media management and ad spend

Strategy & setup: $1,500.00
Content creation: $2,000.00
Monthly management: $1,500.00
Subtotal: $5,000.00
GST (5%): $5,000.00 × 0.05 = $250.00
QST (9.975%): $5,000.00 × 0.09975 = $498.75
Invoice Total: $5,748.75

Frequently Asked Questions

What if my customer is in a different province than me?

You charge tax based on the place of supply - usually where your customer is located or where the service is performed. For most services delivered remotely, charge the tax rate for your customer's province.

Do I charge tax on services provided to US clients?

Generally, no. Services provided to customers outside Canada are typically zero-rated (0% tax). However, keep documentation proving the customer is outside Canada.

How do I handle tax on invoices with multiple line items?

Calculate tax on the subtotal of all taxable items. If some items are tax-exempt (like basic groceries or medical services), calculate tax only on the taxable portion.

When do I remit GST/HST to the CRA?

Filing frequency depends on your annual revenue:

How do I calculate GST on a receipt that includes tax?

Use the reverse calculation: divide the total by 1.05 (for 5% GST) to get the subtotal. The difference is the GST amount. For example, a $105 total ÷ 1.05 = $100 subtotal, so GST was $5.00.

Is GST the same as HST?

Not exactly. GST (Goods and Services Tax) is the federal 5% tax. HST (Harmonized Sales Tax) combines federal GST with provincial tax into a single rate (13% in Ontario, 14% in Nova Scotia, 15% in New Brunswick, Newfoundland and Labrador, and PEI). In HST provinces, you charge one combined rate instead of separate taxes.

Do I charge GST on tips or gratuities?

No. Voluntary tips and gratuities are not subject to GST/HST because they are not considered payment for a supply. However, mandatory service charges (like automatic 18% for large groups) are taxable.

How do I handle GST on deposits or partial payments?

GST/HST is charged when the invoice is issued, not when payment is received. If you invoice $1,000 with $130 HST and the client pays a $500 deposit, you still owe $130 HST to CRA (proportionally over your filing period).

Can I claim GST back on business expenses (Input Tax Credits)?

Yes, if you're GST/HST registered. You can claim back the GST/HST you paid on business expenses by claiming Input Tax Credits (ITCs) when you file your GST/HST return. This reduces your net tax owing to CRA.

What's the penalty for GST calculation errors?

CRA charges interest on underpayments (currently around 5-6% annually). Repeated or significant errors can result in penalties of 5% of the balance owing plus 1% per month. Using invoicing software like iBill helps prevent calculation errors.

Mastering GST/HST Calculation: Formulas, Rounding, and Multi-Province Math

Accurate GST/HST calculation is more than just multiplying a subtotal by a tax rate. Canadian businesses face reverse calculations, rounding decisions, multi-province variations, partial payment allocations, and foreign currency conversions. This section walks through the precise math behind each scenario so you can ensure every invoice is CRA-ready.

Reverse GST Calculation: Extracting Tax From a Total

When you know the final amount a customer paid but need to determine how much GST was included, use the reverse calculation formula. For GST-only provinces (Alberta, BC, Saskatchewan, Manitoba), divide the total by 1.05 to find the pre-tax subtotal, then subtract: GST = Total - (Total / 1.05). For Ontario at 13% HST, divide by 1.13. For example, if a client paid $525.00 in Alberta, the subtotal is $525.00 / 1.05 = $500.00, and the GST portion is $25.00. In Ontario, a $565.00 payment means $565.00 / 1.13 = $500.00 subtotal with $65.00 HST. This is essential when reconciling payments received or issuing credit notes. Use our GST/HST Calculator to verify your reverse calculations instantly.

CRA Rounding Rules: Per Line Item vs. Invoice Total

CRA allows two acceptable methods for rounding GST/HST amounts. The first method rounds tax to the nearest cent on each individual line item before summing them. The second method calculates tax on the invoice subtotal and rounds once at the end. Both are ready, but they can produce slightly different results on multi-line invoices. For example, three line items at $33.33 each: per-item rounding gives 3 x $1.67 = $5.01 GST, while total-based rounding gives $99.99 x 0.05 = $5.00 GST. The difference is only a penny, but consistency matters. Pick one method and apply it uniformly across all invoices. CRA expects you to use the same method throughout a reporting period.

Multi-Province Calculation Examples

The same $1,000 invoice produces very different totals depending on the customer's province. In Ontario (13% HST): $1,000 + $130.00 HST = $1,130.00. In British Columbia (5% GST + 7% PST): $1,000 + $50.00 GST + $70.00 PST = $1,120.00. In Quebec (5% GST + 9.975% QST): $1,000 + $50.00 GST + $99.75 QST = $1,149.75. Note that Quebec QST is calculated on the subtotal only (not compounded on GST) since 2013. In Alberta (5% GST, no provincial tax): $1,000 + $50.00 GST = $1,050.00. In Nova Scotia (14% HST): $1,000 + $140.00 HST = $1,140.00. Try our province-specific tools: Ontario HST Calculator and Quebec QST Calculator.

Partial Payments and Installment GST Allocation

When a client pays an invoice in installments, CRA requires that GST/HST be allocated proportionally to each payment. If a $1,130.00 Ontario invoice (including $130.00 HST) is paid in two installments of $565.00, each payment includes $65.00 of HST. The formula is: HST per payment = Payment Amount / Total Invoice Amount x Total HST. For uneven splits, such as a $400 first payment on that same invoice: HST portion = ($400 / $1,130) x $130 = $46.02. This proportional allocation is important for cash-basis GST/HST reporting, where you remit tax in the period you receive payment, not when you issue the invoice.

Foreign Currency Invoices: Converting to CAD for GST

If you invoice in USD, EUR, or another foreign currency, GST/HST must still be calculated and reported in Canadian dollars. CRA requires you to convert using the Bank of Canada exchange rate on the date of the transaction (the invoice date for accrual-basis filers, or the payment date for cash-basis filers). For example, a US$1,000 invoice issued on a day when the Bank of Canada USD/CAD rate is 1.3650 means your taxable supply is CAD $1,365.00, and 5% GST = $68.25. You can display the foreign currency amount on the invoice for the client's convenience, but your GST/HST records must reflect the Canadian dollar equivalent. Keep a record of the exchange rate used and its source for audit purposes.

Try Our Tax Calculators

Skip the math - use our instant calculators

GST/HST Calculator (All Provinces) Ontario HST Calculator (13%) Quebec QST Calculator

More Tax & Invoice Resources

CRA Invoice Requirements
Compliance guide
Invoice Generator
Create invoices easily
Invoice Templates
Professional formats
Canadian Invoice Software
All provinces

Create CRA-Ready Invoices Automatically

iBill.ca calculates GST, HST, PST, and QST automatically for every invoice.

Get Started Now

• CRA-ready