The Tax code is NOT entered into a return.
Your PAYE tax code is provided by HMRC to your employer or pension provider, in order to work out how much tax to take off your pay each month. This should mean that the correct amount of tax is collected from your pay throughout the tax year and minimise over-payment and under-payments.
Your tax code is based on your personal allowance, which is then adjusted for other items like estimated pension contributions or any benefits you receive. If these adjustments are estimated correctly and your circumstances do not change during the tax year, you should not have any additional tax to pay at the end of the tax year.
PLEASE NOTE: The tax code does not affect the amount of personal allowance available to you and there is nowhere on the tax return for you to alter your personal allowance.
At the end of the tax year HMRC and TaxCalc take your actual income and benefits received and deduct your personal allowances to work out how much tax you should pay – or how much should be repaid to you. This calculation looks at the actual income and expenses, you do not need to enter your tax code in TaxCalc. Note you may need to enter some of the figures used by HMRC in the calculation. The return itself would only be able to cater for scenarios where more tax has been collected at source. Please see the instructions below on where to enter this on the 2022-23 return. If your tax code has been adjusted to collect less tax at source, this would usually require an adjustment post submission however we would recommend contacting the Self Assessment helpline to verify this information for your scenario.
SimpleStep Mode: Browse to Working out your tax > tick the box for Do you currently have any income taxed under PAYE? > browse to Collecting tax through PAYE and declare the adjustment in the box labelled Underpaid tax for earlier years included in your tax code for 2022-23.
HMRC Forms Mode: Tax Calculation > Page 1 > Box 7.