UK Tax Toolbox
Side Hustle Tax Calculator UK
Use this calculator if you earn extra income outside your normal job and want a quick estimate of possible UK tax.
UK Tax Toolbox
Side Hustle Tax Calculator UK
See how your side income may affect your overall tax bill alongside your main job.
Examples: platform fees, software, postage, internet, equipment, advertising, tools or subscriptions.
Most people with low expenses compare this against actual costs. Do not claim both for the same income.
When does a side hustle become taxable?
Understand the £1,000 trading allowance and reporting thresholds.
Employed and self-employed at the same time
See how PAYE salary and separate business profit work together.
How much should a sole trader save for tax?
Build a tax pot around profit, other income and payments on account.
Need more context?
Read our practical UK tax guides for resellers, creators and side hustlers.
Visit tax guidesHow this guidance is reviewed
Author
Written and maintained by UK Tax Toolbox, led by founder Conor Dwyer. Calculator assumptions are checked against the public sources linked on the page.
Last reviewed
12 August 2026
Basis of guidance
Public HMRC and GOV.UK guidance, published tax thresholds and the calculator assumptions stated on each page.
Useful official references
Spot something that looks out of date? Use the contact page to flag corrections. Important tax decisions should still be checked with HMRC or a qualified adviser.
Practical calculator guidance
Estimating side-income tax alongside PAYE
This calculator is for a trade or freelance activity carried on alongside employment. Enter the main salary and gross side-income figures for the same tax year. The estimate is most useful after distinguishing taxable trading receipts from reimbursements, personal transfers and sales of personal possessions.
Your salary changes the side-income result
PAYE normally collects tax on employment income, but it does not automatically settle tax on a separate trade. Salary can use the Personal Allowance and occupy tax bands before side-hustle profit is added. A person near a band boundary can therefore see a different result from somebody with identical side income but no job. Use expected full-year salary rather than one month’s net pay, and retain the P60 or final payslip used.
Aggregate trading income before checking £1,000
The trading allowance is not a separate £1,000 amount for every app or service. Freelance work, creator income, reselling and other trading receipts may need to be considered together depending on the facts. Cash jobs, bank transfers and payments collected through different platforms should be reconciled rather than treated as unrelated because they arrived by different methods. The gross-income test is applied before costs. If reporting is needed, compare supported actual expenses with the allowance and avoid deducting both from the same income.
Plan cash flow, not only the final tax
The result estimates liability but does not show every Self Assessment payment date. A first substantial bill can be accompanied by a payment on account towards the following year. Revisit the estimate quarterly, set aside money as income arrives and use the payments-on-account tool when the projected bill becomes material. If income falls, do not reduce advance payments without a supportable forecast.
Worked example
An employee expects £36,000 of salary and earns £7,200 from weekend design work. Software, payment fees and the supported business share of equipment total £1,400, giving provisional side-hustle profit of £5,800. The calculator considers the £36,000 salary before estimating tax on that profit. The employee retains their P60, invoices, expense evidence and checks whether Self Assessment registration is required.
Best for
- Freelancers
- Part-time sellers
- Weekend side hustles
- Gig economy income
- Second income streams
- People with PAYE plus extra income