What is 400 square feet in regular feet?

Answer 1

"Regular" feet are used to measure how long something is, like a rope,

or how far something is, like the house down the street.

You can't use those at all to measure how much paint you need for a wall,

or how much rug you need for a floor.

To do that kind of measurements, you need a new kind of unit, like "square feet".

They're completely different from regular feet. You can't change one into the other.

I don't care how many feet long a piece of string is ... you can't cover a floor with it.