Form SA102 is the supplementary schedule to the UK Self Assessment tax return (SA100) used to report income earned as an employee or company director under the Income Tax (Earnings and Pensions) Act 2003 (ITEPA 2003).
Even though Pay As You Earn (PAYE) deducts income tax and National Insurance at source, hundreds of thousands of UK taxpayers must complete SA102 to reconcile underpayments, declare taxable benefits in kind, or claim tax relief on un-reimbursed employment expenses.
When You Must Complete Form SA102
HMRC requires Form SA102 if you received earnings from an employment or directorship during the tax year and any of the following apply:
- Company Directors: Statutory office holders must declare all directorship earnings, whether salary, bonuses, or director fees.
- Benefits in Kind (P11D): You received non-cash perks (company car, fuel, private health insurance, low-interest director loans) reported on Form P11D.
- High Earners (£100,000+): Your adjusted net income exceeded £100,000, triggering the £1 for every £2 personal allowance taper under Section 35 of the Income Tax Act 2007.
- Multiple Employments: You changed jobs or held overlapping employments, resulting in incorrect tax code allocations across PAYE schemes.
- Employment Expenses over £2,500: You incurred eligible job expenses that you wish to claim against employment earnings.
Sourcing Your Numbers: P60, P45 & P11D
To complete Form SA102 accurately, gather your statutory payroll documentation:
- Form P60 (End of Year Certificate): Issued by your employer after 5 April. Box 1 of SA102 takes your total pay before tax, and Box 2 takes the total UK tax deducted under PAYE.
- Form P45 (Details of Employee Leaving): If you left a job before 5 April, Parts 1A or 2/3 provide your final taxable pay and tax deducted for that specific employment. Each distinct employment requires a separate SA102 schedule.
- Form P11D (Expenses and Benefits): Issued by employers by 6 July following the end of the tax year. Each section of Form P11D (e.g. company car, private healthcare, interest-free loans) maps to corresponding boxes on page E1 of SA102.
Taxable Benefits in Kind (BIK)
Under ITEPA 2003 Part 3, benefits provided by reason of employment are treated as taxable employment income. Common items reported on SA102 include:
- Company Cars (Box 9): Calculated using the vehicle's list price multiplied by the appropriate CO2 emissions percentage band.
- Car Fuel Benefit (Box 10): Calculated by multiplying the fuel benefit charge multiplier (£27,800 for recent years) by the vehicle's CO2 percentage.
- Private Medical Insurance (Box 15): The exact annual premium paid by the employer to provide healthcare cover for you or your family.
- Services & Assets Provided (Box 14): Living accommodation, employer-provided mobile phones beyond statutory exemptions, or personal use of corporate assets.
Allowable Employment Expenses (Section 336 ITEPA)
The statutory test for employment expense deductibility under Section 336 ITEPA 2003 is notoriously strict: the employee must be obliged to incur and pay the expenses, and they must be incurred wholly, exclusively, and necessarily in the performance of the duties of the employment.
Allowable deductions include:
- Professional Fees & Subscriptions (Box 19): Annual subscriptions to professional bodies approved by HMRC under Section 344 ITEPA (e.g. GMC, Law Society, ACCA, ICE) where membership is directly relevant to your employment.
- Business Travel & Mileage Allowance (Box 17): If you use your personal vehicle for business travel (excluding ordinary commuting between home and permanent workplace) and your employer pays less than HMRC's Approved Mileage Allowance Payments (AMAP) rate (45p per mile for the first 10,000 miles, 25p thereafter), you can claim Mileage Allowance Relief for the difference.
- Working From Home Allowance: If your employer requires you to work from home under a formal arrangement, you can claim tax relief for documented additional household expenses or HMRC's flat rate of £6 per week.