TAX YEAR 2026/27
What a 2026/27 tax estimate can—and can’t—tell you
Business profit, employment income and Self Assessment are related, but they are not interchangeable. Here is how to read the difference.
Start with the year, not the calendar
The 2026/27 UK tax year runs from 6 April 2026 to 5 April 2027. Make sure the income, expenses and employment figures you compare cover the same period. Our web estimator explicitly supports 2025/26 and 2026/27 for England, Wales and Northern Ireland. It does not silently apply those Income Tax bands to Scotland or to another tax year.
Profit is not the same as turnover
Turnover is business income before costs. Profit is what remains after the allowable expenses you deduct. If you also have an employed job, taxable employment pay is separate from that turnover. Employment and business income share your Personal Allowance; you do not get a second allowance just because you have a side business.
Separate the business effect from the overall payment
To see the additional Income Tax caused by business profit, compare tax on combined income with tax on employment income alone. Then consider self-employed National Insurance where it applies. The estimated Self Assessment balancing amount also reflects actual PAYE income tax already deducted. It can differ substantially from the extra tax attributable to the business.
An estimate is not your HMRC account
Your actual account may include payments on account, earlier balances, adjustments and interest. Personal circumstances such as pensions, student loans and other income can also change your position. Use the calculator for planning within its stated scope, not as confirmation of a tax return or as a substitute for checking your HMRC account.
