What you need to know:
Gross Pay – total of all PAYE income from UK employment.
Leaving UK Tax Paid – total of all UK tax paid in one full tax year.
The UK Tax Year – the UK tax year runs from the 6th April one tax year to the 5th April the next.
The Leaving the UK Tax Back Calculator works out an approximation of how much leaving the UK tax back you may be due in this current and previous four tax years.