Short answer
SDLT affects entry cost. CGT can affect exit proceeds for personally owned property. Section 24 can affect annual rental tax for personal buy-to-let ownership.
How it works in Koreograph
Tax assumptions are included to help you compare scenarios on a more realistic basis. They are estimates for modelling and should be confirmed before purchase or disposal.
Developer view
Do not judge a deal only before tax. For investors, the difference between pre-tax and after-tax cashflow can change the decision. For developers and flips, the exit tax and sale timing can decide whether the margin is strong enough.