How is the tax during tax year in the United Kingdom calculated?

24th Jul 2020

When does the British tax year start? When does it end?

The British Tax year is always from the 6th of April to the 5th of April - unlike what we are used to in most countries - from 1st of January to the 31st of December.

This makes it a bit tricky when trying to calculate your taxes. Here is how it breaks down for the following years:


The earning document P60 always shows the ending date, for example, "Tax year to 5 April 2018". It means it is about the tax year of 2017/2018 and you need to use the NeoTax calculator of 2017.

The P45 always has a "Leaving date" field. For example, 12.03.2019. In this case, the tax year would be 2018.04.06 - 2019.04.05 using the NeoTax calculator of 2018.

Check how much you can refund from the U.K. in free online calculator on

I want to file a tax return