Self-assessment income details
How to estimate Self Assessment tax
Enter self-employed turnover, expenses or the trading allowance, other taxable income, pension contributions, student loan plans, and tax year to estimate Income Tax, National Insurance, and student loan repayments.
Enter turnover
Enter gross self-employed trading income for the tax year before expenses.
Choose your deduction
Use the £1,000 trading allowance or untick it and enter actual allowable business expenses.
Add other income and pension
Include employment or other taxable income. Enter pension contributions to receive tax relief and potentially reduce Personal Allowance taper.
Select Scottish taxpayer if applicable
If you live in Scotland, tick the Scottish taxpayer checkbox to use Scottish Income Tax rates instead of UK rates.
Add student loan plans
Select your student loan plan(s) to estimate compulsory repayments based on your profits.
Review tax, NI, and student loans
The result separates Income Tax, Class 2 National Insurance, Class 4 National Insurance, student loan repayments, total liability, and net profits.
Frequently Asked Questions
What is the Class 2 NI rate for 2026/27?
Class 2 National Insurance is £3.45 per week for 2026/27. You pay this if your self-employment profits exceed £6,725 per year.
What are the Class 4 NI rates?
Class 4 National Insurance is 6% on profits between £12,570 and £50,270, and 2% on profits above £50,270 for 2026/27.
Do I need to file a Self Assessment if I earn less than £1,000?
If your self-employment income is below £1,000, you may not need to file a Self Assessment tax return due to the trading allowance. However, you may still need to file if you have other reasons to do so.
When is the Self Assessment deadline?
The deadline for online Self Assessment tax returns is 31 January following the end of the tax year. For 2026/27, the deadline is 31 January 2028.
What are the Scottish Income Tax rates?
Scottish taxpayers pay different Income Tax rates: 19% (starter), 20% (basic), 21% (intermediate), 42% (higher), 45% (advanced), and 48% (top) for 2026/27. The Personal Allowance and National Insurance rates remain the same as the rest of the UK.
How do student loan repayments work for self-employed?
Self-employed people pay student loan repayments through Self Assessment. Repayments are calculated on profits above your plan threshold: Plan 1 (£26,900), Plan 2 (£29,385), Plan 4 (£33,795), Plan 5 (£25,000), and Postgraduate (£21,000). Undergraduate plans charge 9% above the threshold, while postgraduate loans charge 6%.
Do pension contributions reduce my tax?
Yes. Pension contributions reduce your adjusted net income, which can help preserve your Personal Allowance if you're near the £100,000 taper threshold. You receive tax relief at your marginal rate through your Self Assessment return.
What is the Personal Allowance taper?
Your Personal Allowance (£12,570) is reduced by £1 for every £2 of adjusted net income over £100,000. Adjusted net income includes self-employment profits plus other income, minus pension contributions. Income over £125,140 loses the Personal Allowance entirely.
Can I claim both the trading allowance and actual expenses?
No. You must choose one or the other. Use the trading allowance (£1,000) if your actual expenses are less than £1,000. Use actual expenses if they exceed £1,000, as this gives you a larger deduction.