How to convert luminous intensity in candela (cd) to illuminance in lux (lx).
You can calculate lux from candela and distance from light source.
You can't convert candela to lux, since lux and candela do not represent the same quantity.
The illuminance Ev in lux (lx) is equal to 10.76391 times the luminous intensity Iv in candela (cd),
divided by the square distance from the light source d2 in square feet (ft2):
Ev(lx) = 10.76391 × Iv(cd) / (d(ft))2
So
lux = 10.76391 × candela / square feet
Or
lx = 10.76391 × cd / ft2
The illuminance Ev in lux (lx) is equal to the luminous intensity Iv in candela (cd),
divided by the square distance from the light source d2 in square meters (m2):
Ev(lx) = Iv(cd) / (d(m))2
So
lux = candela / square meters
Or
lx = cd / m2