By default, the current tax year is applied, but if you wish to see calculations for other years, you can select them from the drop-down menu. Where tax rates change during the year, a blended rate is applied.
HMRC may provide a non-standard tax code if your situation calls for it. The letter refers to your specific situation and is used to adjust your personal allowance. Most codes also contain a number, which usually refers to the amount you can earn before any tax is due, divided by 10.
The NI category letter determines what contributions employers and employees need to make when running payroll. Most individuals have a NI category letter of A.
Business Asset Disposal Relief (‘BADR’)