Why Does Self Assessment Show Tax Owed Despite PAYE Deductions?

If you are a sole trader and file a Self Assessment tax return, you might notice that the tax calculation shows an amount owed even though you have paid tax through PAYE (Pay As You Earn) on other income, such as employment wages. This can be confusing, but there are practical reasons for this situation.

Understanding PAYE and Self Assessment

PAYE is a system where your employer deducts Income Tax and National Insurance contributions from your wages or pension before you receive them. This system works well for straightforward employment income.

However, as a sole trader, your business profits are not taxed through PAYE. Instead, you must report all your income and allowable expenses via a Self Assessment tax return after the tax year ends (5 April). HM Revenue and Customs (HMRC) then calculates your total tax liability based on all your income sources combined.

Why You Might Owe Tax Despite PAYE Deductions

• Additional Income Outside PAYE: Your sole trader profits are separate from your employment income. PAYE tax deductions only cover your employment income, not your self-employed earnings.
• Different Tax Treatment: Sole trader profits are subject to Income Tax and Class 2 and Class 4 National Insurance contributions, which are not deducted through PAYE.
• Tax Allowances and Thresholds: Your personal allowance and tax bands apply across all income. If your combined income exceeds certain thresholds, you may owe additional tax on your self-employed profits.
• Underpayments or Adjustments: If your PAYE tax deductions were based on an estimate or did not fully cover your total tax liability, the Self Assessment will show the balance due.

Practical Example

Suppose you work part-time and earn £15,000 a year through PAYE, with tax deducted at source. You also run a small sole trader business and make a profit of £10,000 in the same tax year. Your employer has deducted tax on the £15,000, but the £10,000 profit is untaxed until you submit your Self Assessment return.

When you file your return, HMRC adds your income together (£25,000 total) and calculates the tax due after your personal allowance. The tax already paid through PAYE is credited, but you will owe Income Tax on the £10,000 profit plus Class 2 and Class 4 National Insurance contributions due on your self-employment earnings.

What You Should Do

1. Keep Accurate Records: Maintain detailed records of your business income and expenses to complete your Self Assessment accurately.
2. File Your Return on Time: Submit your Self Assessment tax return by the deadline, usually 31 January following the end of the tax year.
3. Pay Any Tax Due Promptly: Pay the balance shown by HMRC by the payment deadline to avoid interest or penalties.
4. Check Your Tax Calculation: If you believe the tax owed is incorrect, review your return and records or contact HMRC for clarification.

Remember, PAYE deductions do not cover Income Tax or National Insurance on self-employed earnings. The Self Assessment system ensures all your income is taxed correctly, which can result in a tax bill even if you pay tax through PAYE on other earnings.

Official reference: https://www.gov.uk/self-assessment-tax-returns. Always check the latest official guidance. Related forms: Browse our form category.

Important: This article provides general information. Government rules, forms and procedures can change, and this article may not reflect the latest updates. Check current GOV.UK guidance or the relevant authority before relying on it. ITG & Co. is independent and is not affiliated with a government department.