Capital gains on Conversion to flats

[venture53]

Could somebody please help with the CGT calculations on a converted property. The house was bought in 1985 for £90,000. It was the main residence initially and then converted into three flats in 1992 and rented out. The property has been rented out since 1992. The individual flats are now each worth £160,000 approx. If they are sold now, what is the CG and how is it calculated using any reliefs or indexation. Thanks for your help

[greybags1]

Have a look at HMRC's guidance here https://www.gov.uk/hmrc-internal-manuals/capital-gains-manual/cg65200p