The choice of the correct foil size depends on your weight, your skill level, and the cruising speed desired:
A large surface offers more lift (faster take-off), but will also reach its maximum speed quicker.
A small surface is slower to take off, but is more manoeuvrable, and will reach higher speeds.
The heavier the load (rider+board), the larger the wing required.
For example, a 1600 cm² wing is suitable for a person weighing 80 kg, with an intermediate level in SUPfoiling.