There is no single correct wire size that a website can give you for a 50-amp EV circuit. That circuit is usually selected to carry 40 amps of continuous charging (40 × 1.25 = 50) at 240 volts, or 9.6 kW. Ampacity, voltage drop, copper versus aluminum, insulation and terminal temperature ratings, and the length of the run all change the conductor you actually need. The 40-amp-circuit page explains the same limits; they do not go away at 50 amps, and a longer outdoor or detached-garage run makes them more important, not less.
A 50-amp circuit also has to survive the load calculation at the service, not just at the branch. If the only reason you want 50 amps is future-proofing, read the 14-50 page and confirm that the panel has room for 40 A continuous today. Then leave the conductor choice to a licensed electrician. This site will not convert a forum gauge into a shopping list, for 50-amp circuits or for any other size.
Start with the current you need and the panel calculator, then have the run measured and designed under permit.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.