Estimate your Self Assessment tax bill for the 2025/26 tax year.
Total Tax Bill
£7,311
Payment on account: £3,656
Total Income
£40,000
Personal Allowance
£12,570
Income Tax
£5,486
National Insurance
£1,825
First Payment (31 Jan)
£10,967
Self Assessment is the system HMRC uses to collect Income Tax, primarily from individuals and businesses with income that isn't taxed at source. This often includes the self-employed, landlords, and those with significant investment income. Understanding your obligations is key to managing your finances effectively and avoiding unexpected penalties. This Calculator Site tool is designed to give you a clear estimate of your potential liability.
The process involves declaring your total income from all sources for a given tax year (6th April to 5th April) and calculating the tax owed. For many, the biggest challenge is not just the tax itself, but also navigating the system of Payments on Account. For a detailed breakdown of your earnings after tax, you might find our Take-Home Pay Calculator a useful next step.
The 'Payments on Account' Trap
If your Self Assessment bill is over £1,000, HMRC requires you to make advance payments for the *next* tax year. These are called 'Payments on Account'. Each payment is typically 50% of your previous year's bill. The first is due on 31st January (along with your main tax bill) and the second on 31st July. This can lead to a surprisingly large first bill, sometimes up to 150% of your calculated tax, which catches many people out.
Several key thresholds determine your final tax bill. These figures are essential for anyone completing a Self Assessment return. If your business is a limited company, remember to also check our Corporation Tax Calculator.
£12,570
Personal Allowance
£50,270
Higher Rate Threshold
£500
Dividend Allowance
How to use this Calculator Site tool
To estimate your tax bill, simply enter your income from various sources into the fields provided. Include your salary from employment, profits from self-employment, rental income, dividends, and any savings interest. The calculator will automatically apply the current tax rates and thresholds for the 2025/26 tax year to provide a comprehensive breakdown of your estimated Income Tax, National Insurance, and any Payments on Account due. For official guidance on filing, visit GOV.UK Self Assessment guide.
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