Self-Assessment Tax Calculator
Estimate income tax on sole-trader profits.
Enter income and expenses
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Self-assessment tax calculator guide for UK freelancers
WeCovr's self-assessment tax calculator helps UK freelancers estimate income tax, backed by FCA-authorised guidance and 900,000+ policies issued across protection products. We also support private medical insurance UK choices, while this guide focuses on tax basics for planning only.
What this self-assessment calculator estimates
The calculator estimates income tax on profits after allowable expenses. It does not include National Insurance, student loans, or other adjustments.
Use it to sense-check cash flow before submitting returns.
Uses current-style income tax bands.
Assumes profits are income minus expenses.
Provides an illustrative tax figure only.
Allowable expenses and record keeping
Keep clear records of business costs, invoices, and receipts so expenses are easier to defend if HMRC asks for evidence.
Payment on account awareness
If your bill is above HMRC thresholds, payments on account can mean larger first-year outflows. Plan cash flow for January and July.
Why WeCovr supports freelancer planning
WeCovr provides FCA-authorised guidance with high customer satisfaction ratings. We also offer complimentary access to the CalorieHero AI calorie tracking app and discounts when customers take PMI or Life insurance. If you are comparing private medical insurance UK policies, we can help you access private health cover through a trusted PMI broker.
Data sources and guidance references
This guide references HMRC guidance on self-assessment deadlines and income tax bands.
Key self-assessment milestones
| Milestone | Typical timing | What to prepare | Why it matters |
|---|---|---|---|
| Register for self-assessment | After starting trade | UTR + records | Enables filing |
| Tax return deadline | 31 January | Income and expenses | Avoids penalties |
| Payment on account | Jan/Jul | Cash reserves | Smooths cash flow |
Related WeCovr resources
FAQs
Does this include National Insurance?
No. This calculator focuses on income tax only. Use a full tax tool or adviser for NI estimates.
Can expenses reduce my tax bill?
Yes. Allowable business expenses reduce taxable profit when documented correctly.
Is this tax estimate guaranteed?
No. It is a planning estimate and should be checked against current HMRC guidance.
When should I file my return?
The online deadline is typically 31 January after the tax year ends.