Calculating CGT liability from income

When calculating CGT on a second home, you have to state your income to work out what proportion is taxed at 18% or 24%. I don't understand how, if you sell your rental property half way through a year, are you able to state what you are earning until that tax year is complete? So for instance I am employed and have a second home i am selling in say May 2025. I won't know exactly what my income is until April 2026 the following year (i could change job or loose my job). So how do you calculate your CGT liability? Secondly, do I report this gain via my tax self assessment? Many thanks

Hi ,
 

You need to give an estimate of your icnome when reporting on the 60 day return and at the end of the year, you then include the gain in the full tax return which is then based on your actual income. Thank you .