How should I use the villa calculator alongside an architect’s concept design?

Run the calculator early to set a realistic budget conversation before your architect finalises a concept, then re-run it once the concept design gives you a firmer sense of built-up area, storey count and outdoor scope. This sequence prevents a beautiful concept design from being presented to you before anyone has checked whether it fits a realistic budget. If the two numbers diverge significantly once the concept is ready, that is exactly the right moment to revisit scope before drawings are locked.