Conversion Equation

Where 'd' is the distance from the light source in meters.

In case, If you would like to use feet instead of meters, then convert sq. meter to sq. feet. 

ie; 1 sq. mt. = 10.76391 sq. ft.

Lux

Lux (lx) is the SI unit of illumination. It indicates the illumination intensity of an area.

One Lux is equal to One Lumen per square meter.

illuminance (Ev) is the amount of luminous flux per unit area.

Candela

1 candela is equal to 1000 millicandela.

Candela (cd) is the SI unit of Luminous Intensity. It indicates the strength of light emission and is defined as the luminous power per unit solid angle emitted by a light source in a particular direction.

Unit Solid Angle means the solid angle of a sphere subtended by a portion of the surface whose area is equal to the square of the sphere's radius.

Luminous Intensity (Iv) of a light source is the emitted luminous power or luminous flux per unit solid angle.