Self-Employed Tax Calculator
Work out the tax on self-employed or side hustle profit in the UK, US or Canada, how much to put aside each month and when the payments are due.
Reviewed by Dany, RightSums team · Updated
Runs in your browser. Free, no sign-up.
salary-tax · Daily life · UK & US & Canada
Enter what your business brings in, your expenses and any pay from a job, and the calculator works out the tax you owe on the profit and how much to put aside each month. In the UK it covers Income Tax, Class 4 National Insurance, Class 2, student loan and the £1,000 trading allowance for 2026/27, with payments on account and the first-year 31 January bill. In the US it adds self-employment tax, federal and state income tax and the 2026 quarterly estimated tax dates. In Canada it covers both halves of CPP, CPP2 and income tax by province, with the CRA instalment dates. Job income is stacked first, so a side hustle is taxed at the right rate. It is an estimate, and everything runs in your browser.
Accepted inputs
- Country: UK, US or Canada
- Self-employed income (turnover) for the year
- Allowable expenses, or the £1,000 trading allowance in the UK
- Yearly pay from a job (PAYE, W-2 or T4), if you have one
- UK: Scottish taxpayer, student loan plan, voluntary Class 2
- US: filing status, state, the 20% QBI deduction, last year's tax for the safe harbour
- Canada: province or territory (Quebec not covered)
Outputs
- Profit after expenses
- Each tax: Income Tax and Class 4 NI, self-employment tax and federal and state income tax, or CPP, CPP2 and income tax
- Total tax for the year and the effective rate on profit
- Share of each pound or dollar of income to set aside
- Monthly amount to put aside
- Payment dates and amounts: UK payments on account, US estimated tax, Canada instalments
- UK first-year 31 January bill
How to use the Self-Employed Tax Calculator
- Enter your self-employed income, your allowable expenses and any yearly pay from a job, then pick the UK, the US or Canada.
- The calculator takes expenses (or the UK £1,000 trading allowance) off your income to find your profit, then taxes it on top of your job pay so the right bands apply.
- It adds the self-employed contributions for your country: Class 4 National Insurance in the UK, 15.3% self-employment tax in the US, or both halves of CPP in Canada.
- It divides the total by 12 for a monthly set-aside figure and lists when each payment is due, including UK payments on account, US quarterly estimated tax and CRA instalments.
Frequently asked questions
How much tax do I pay when self-employed?
In the UK you pay Income Tax and Class 4 National Insurance on your profit. With £40,000 of income and £5,000 of expenses in 2026/27, profit is £35,000: Income Tax is £4,486 and Class 4 is £1,345.80, so £5,831.80 in total, about 16.7% of profit. A job paid through PAYE uses your allowance first, so side income is taxed higher.
How much should I put aside for tax when self-employed?
Put aside the year's tax divided by 12. On £40,000 of UK income with £5,000 of expenses that is £486 a month, or 14.6% of everything that comes in. In the US, $60,000 of income and $10,000 of expenses for a single filer means about $9,732 of federal tax, or $811 a month, before any state tax.
What is Class 4 National Insurance?
It is the National Insurance self-employed people pay on profits through Self Assessment. For 2026/27 it is 6% on profits between £12,570 and £50,270 and 2% above that. On £35,000 of profit it comes to £1,345.80. Class 2 is no longer charged: at £7,105 or more it is treated as paid, and below that you can pay £3.65 a week voluntarily.
How much is self-employment tax in 2026?
It is 15.3% on 92.35% of your net profit: 12.4% for Social Security up to the $184,500 wage base (less any W-2 wages) and 2.9% for Medicare, plus 0.9% above $200,000 ($250,000 joint). On $50,000 of profit it is $7,064.78, and half of it, $3,532.39, is deducted before income tax.
When do I pay tax as a freelancer?
In the UK the bill for 2026/27 is due by 31 January 2028, and if it is £1,000 or more you also pay half of it in advance on 31 January and 31 July. On a £5,831.80 bill your first 31 January payment is £8,747.70. US estimated tax is due 15 April, 15 June, 15 September and 15 January; Canadian instalments on the 15th of March, June, September and December.
Sources
The rates and rules in this tool come from:
- Canada Revenue Agency: Canadian income tax rates for individuals, current and previous years
- Canada Revenue Agency: T4127 jan payroll deductions formulas computer programs
- Canada Revenue Agency: T4127 jul payroll deductions formulas
- Canada Revenue Agency: CPP contribution rates, maximums and exemptions
- Canada Revenue Agency: Second additional CPP (CPP2) contribution rates and maximums
- Canada Revenue Agency: EI premium rates and maximums
- Canada Revenue Agency: Adjustment personal income tax benefit amounts
- GOV.UK: Self-employed National Insurance rates
- GOV.UK: Income Tax rates and Personal Allowances : Current rates and allowances
- GOV.UK: Income Tax in Scotland: Current rates
- GOV.UK: Understand your Self Assessment tax bill: Payments on account
- GOV.UK: Tax-free allowances on property and trading income
- GOV.UK: Repaying your student loan: How much you repay
- GOV.UK: Self Assessment tax returns: Deadlines
Guides that use this tool
- Making Tax Digital for Income Tax: does it apply to you, and when?
- National Insurance rates 2026/27: what you pay and how it works
- Payments on account: when they're due and how to reduce them
- Tax year dates UK: when the tax year starts, ends and what is due
- What is OASDI tax on my paycheck? The 6.2% Social Security tax
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