Everything you need to know to estimate your self-employment taxes — income tax, social contributions and quarterly installment dates — across Canada, USA, UK, Australia and New Zealand.
Open the Self-Employment Tax CalculatorThe WorkersPool Self-Employment Tax Calculator estimates your total annual tax obligation as a self-employed person — covering income tax at federal and provincial/state level, plus social contributions (CPP in Canada, SE tax in the US, NI Class 4 in the UK, Medicare in Australia, ACC in NZ). It also shows your estimated quarterly installment amounts and due dates.
You enter your gross revenue, deductible business expenses, any employment income from other sources, and RRSP contributions (Canada). The calculator applies the published tax rates and brackets for your country and selected year, then produces a full breakdown: net income, estimated total tax, take-home amount, effective rate and a per-month set-aside guide.
This tool is for planning — understanding how much to set aside and whether installments are required. It is not a tax return and does not replace a qualified accountant.
| Country | Income Tax | Social Contributions | Key Notes |
|---|---|---|---|
| Canada | Federal + provincial (province selector) | CPP — both shares (11.9% combined 2026) | RRSP deduction reduces taxable income |
| USA | Federal + major state | SE tax 15.3% (SS + Medicare) | Half of SE tax is deductible from income |
| UK | Income tax bands | NI Class 4 (6% / 2%) | Class 2 abolished April 2024 |
| Australia | ATO income tax brackets | Medicare Levy 2% | Super contributions shown separately |
| New Zealand | IRD income tax brackets | ACC earner levy | No social insurance equivalent |
Net Income — Gross revenue minus business expenses. This is your taxable self-employment income before personal deductions like RRSP.
Tax Breakdown — Each component shown separately: federal income tax, provincial/state income tax, CPP/SE tax/NI/Medicare, and any applicable levies. Seeing each component helps you understand where the biggest obligations sit.
Effective Tax Rate — Your total estimated tax as a percentage of gross revenue. This is the most useful number for setting aside money on each invoice — not the marginal rate, which only applies to the last dollar earned.
Monthly Set-Aside — How much to transfer to your tax savings account each month based on the annual estimate. Use this as your autopilot rule: every month, move this amount to a separate savings account.
Payment Schedule — Installment due dates for your country with the estimated amount for each. Set calendar reminders immediately.
Tariq now knows to set aside approximately $2,858 per month into a dedicated tax account. He sets up a calendar reminder for each CRA installment date and makes equal quarterly payments throughout the year, avoiding a large lump-sum surprise at filing time.
The Self-Employment Tax Calculator provides rough estimates for planning purposes only — not tax advice. It uses simplified bracket calculations and published rates. It does not account for every deduction, credit, surtax, phase-out, surcharge or special rule that may apply to your situation. Your actual tax bill may differ substantially. Always consult a qualified tax professional (CPA, CA, Enrolled Agent or Tax Agent) before making financial decisions based on any estimate. WorkersPool accepts no liability for tax or financial decisions based on this tool.
Authoritative sources for self-employment tax rates: