Self-Employed Tax Calculator UK

Use this to estimate income tax, National Insurance, payments on account, and take-home for UK self-employment.

Inputs

Showing basic inputs only.

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Scenario planner (A/B/C)

Save three local what-if versions of your current inputs and switch between them.

Scenario A

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Scenario B

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Scenario C

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Results

Updated for selected year
Taxable profit£0.00
Income tax estimate£0.00
Class 2 NI estimate£0.00
Class 4 NI estimate£0.00
Student loan estimate£0.00
Total estimated tax/NI (gross)£0.00
Credits already paid/deducted£0.00
Estimated still to pay£0.00
Estimated overpayment/refund£0.00
Estimated take-home£0.00
Suggested monthly set-aside£0.00

Payment schedule (estimate)

Balancing payment estimate£0.00
Next-year payment on account (each)£0.00
January estimate (balance + first POA)£0.00
July estimate (second POA)£0.00
Calculation assumptions & disclaimer

This calculator is for planning and cashflow budgeting. It does not replace professional advice or your final HMRC Self Assessment calculation.

FAQ

Based on common Self Assessment questions from HMRC/GOV.UK guidance.

Do I need to do Self Assessment if I only made a small amount?

If your total self-employed income is above the trading allowance, you usually need to register and file. The trading allowance is currently £1,000.

What expenses can I include?

Include costs that are wholly and exclusively for business use, such as business travel, office costs, software subscriptions, professional fees, and business-use share of phone/internet.

When is the Self Assessment deadline?

Online tax return deadline is usually 31 January after the tax year ends. Payment deadlines are commonly 31 January and 31 July for payments on account.

What are payments on account?

These are advance payments towards your next tax bill, usually split into two instalments in January and July. This calculator estimates those amounts for planning.

Can I reduce payments on account if my income drops?

Yes, HMRC allows reducing payments on account if you expect a lower bill. Reduce carefully, as underpaying can lead to interest.

Do self-employed people pay National Insurance?

Most self-employed people pay Class 4 National Insurance on profits above the threshold. Some may also be affected by Class 2 rules depending on profit level and eligibility.

What if I cannot pay my tax bill on time?

Contact HMRC as early as possible. You may be able to set up a Time to Pay arrangement rather than missing deadlines without a plan.

Is this calculator the same as my final HMRC bill?

No. It is a planning estimator. Your final bill depends on your complete tax return, exact HMRC records, and your specific tax circumstances.

Need more answers? Visit the full FAQ page.

Official references: deadlines, payments on account, allowable expenses, registering for Self Assessment.