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Updated for 2026/27 Tax Year

Side Hustle Tax
Impact Calculator

Stop guessing your tax bill. Enter your salary and side income to see exactly how your tax bands change and how much you keep.

Input Your Earnings

£

Your Gross PAYE salary before any deductions.

£
£

HMRC Trading Allowance

Active: The £1,000 Trading Allowance was automatically applied to give you maximum tax relief.

Final Take Home Pay£28,320Per Year
Combined Income£34,000
Hustle Tax Liability− £800
Effective Tax Rate16.7%
Combined Allowances Applied
Self Assessment Ready
HMRC 2026/27 Verified

Tax Band Analysis

Basic Rate Efficiency (20%)

Your combined income is safely within the 20% basic rate. Your side hustle profit is taxed at a manageable rate.

Note: This tool assumes a standard 1257L tax code and does not include Student Loan or Pension deductions.

How your side income affects your tax

In the UK, HMRC doesn't treat your side hustle and your main job as separate entities. Instead, they look at your Total Combined Income. When you start earning outside of PAYE, your side hustle profit is essentially "stacked" on top of your job salary.

In Plain English

What is "The Single Allowance Rule"?

You only get ONE £12,570 Personal Allowance. Since your main job usually uses this up, your side hustle income is taxable roughly from pound one - unless you use the £1,000 Trading Allowance to skip registration entirely.

Why combined income matters

The danger for most "hybrid" workers is accidentally crossing into a higher tax band. If your job salary is £45,000 and your side hustle makes £10,000 profit, your total income is £55,000. This means about £5,000 of your side hustle profit is taxed at the 40% Higher Rate instead of the 20% basic rate.

Common Side Hustle Tax Questions

No. This tool is private. Furthermore, filing for Self Assessment doesn't alert your employer unless you choose to pay your tax bill through an adjusted tax code (which we recommend avoiding if you want privacy).
Usually, yes. However, you only start paying Class 4 National Insurance once your side hustle profit exceeds £12,570. If your profit is lower than that, you only pay Income Tax.
You can potentially use these 'trade losses' to offset the tax you paid at your main job, essentially getting a tax refund on your PAYE income. This is a powerful but complex strategy.