Canada Business Number (BN) vs. Personal Tax Number (SIN) Calculator
Tool to help classify and compare amounts associated with a Canada Business Number (BN) and a personal tax number (Social Insurance Number, SIN). Includes Canada-specific guidance and official citations.
- Page updated:
- Jun 10, 2026
- Tool version:
- v1.2.0
Overview
For an unincorporated business in Canada, income earned under your Business Number (BN) is not taxed separately — your net business income flows to your personal (SIN) tax return. Enter your revenue, expenses and marginal rate to see net business income, the estimated tax and your after-tax income, plus whether you must register for GST/HST.
Educational estimate, not tax advice. Incorporated businesses are taxed separately as corporations. For your exact situation, consult the CRA or a tax professional.
Results
Net business income
$55,000.00
Estimated income tax on business income
$16,500.00
After-tax business income
$38,500.00
GST/HST registration
Required — register for a GST/HST account under your BN
Effective tax rate on net income
30 %
How to read the result
- What it means
- The displayed value is an estimate based on your inputs. It represents the calculated scenario under current assumptions, not a guaranteed amount.
- Next step
- Use the result as a starting point. Adjust parameters to compare scenarios and validate with a professional when needed.
- Calculation limits
- The model uses simplified formulas and cannot account for all variables in your specific case (local regulations, personal conditions, temporal changes).
Methodology
For a sole proprietorship or partnership, the Business Number (BN) identifies the business for CRA program accounts (GST/HST, payroll), but the business is not a separate taxpayer — its profit is reported on the owner's personal return filed under their SIN.
- Net business income = business revenue − deductible business expenses.
- Estimated income tax = net business income (if positive) × your combined marginal rate. Because business income stacks on your other income, use your marginal rate.
- After-tax income = net business income − estimated tax.
GST/HST: if revenue over four consecutive calendar quarters exceeds the small-supplier threshold ($30,000), you must register for a GST/HST account (part of your BN) and charge GST/HST. Below it, registration is optional.
Assumptions and limitations: a flat marginal rate (not the full progressive bracket calculation); excludes CPP contributions on self-employment income, the basic personal amount, instalment requirements, and provincial differences. GST/HST collected/remitted is separate from income tax. Estimates only.
Sources: Canada Revenue Agency (CRA) business income and GST/HST registration guidance — see citations.
Glossary+−
- Business Number (BN)
A 9-digit CRA identifier for a business, to which program accounts (GST/HST, payroll, corporate income tax) are attached.
- Social Insurance Number (SIN)
A personal identifier used for an individual's tax return; sole-proprietor business income is reported under the owner's SIN.
- Sole Proprietorship
An unincorporated business owned by one person, whose profit is taxed on the owner's personal return rather than separately.
- Small-Supplier Threshold
The $30,000 revenue level above which GST/HST registration becomes mandatory.
- Marginal Tax Rate
The rate applied to your next dollar of income; business income is taxed at this rate as it stacks on other income.
Key takeaways
Enter revenue, expenses and your marginal rate to see net business income, estimated personal income tax, after-tax income and whether GST/HST registration is required.
Estimate only — excludes CPP, the basic personal amount and progressive brackets. Confirm with the CRA or a tax professional.
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Worked examples
Example: $80,000 revenue, $25,000 expenses, 30% marginal rate
A sole proprietor whose business income is reported on their personal return.
Interpretation
The $55,000 net profit is added to the owner's personal income and taxed at their marginal rate (~$16,500 here), leaving $38,500 after income tax. Because revenue tops $30,000, a GST/HST account under the BN is mandatory.
Frequently asked questions
Does a Business Number mean my business is taxed separately?
Not for a sole proprietorship or partnership. The BN identifies the business for CRA accounts, but the profit is taxed on your personal (SIN) return. Only incorporated businesses are separate taxpayers.
When must I register for GST/HST?
When your revenue exceeds $30,000 over four consecutive calendar quarters (or in a single quarter). Below that you are a 'small supplier' and registration is optional.
Why use my marginal rate?
Business income adds on top of your other income, so it is taxed at your marginal (top) rate rather than your average rate. This gives a more realistic estimate of the extra tax.
Is CPP included?
No. Self-employed individuals also pay both employee and employer CPP contributions on net business income. This tool estimates income tax only; add CPP separately.
Sources & references
- CRA — Business income tax (sole proprietorships and partnerships): https://www.canada.ca/en/revenue-agency/services/tax/businesses/small-businesses-self-employed-income.html
- CRA — When to register for and start charging the GST/HST: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/when-register-charge.html
- CRA — Business Number (BN) registration: https://www.canada.ca/en/services/taxes/business-number.html
Quality & oversight
- Author
- Ugo Candido, MBA
- Maintained by
- Ugo Candido, MBA
- Page updated
- Jun 10, 2026
- Tool version
- v1.2.0