Will laying out in sun w proper body exposure for 20 min be just as effective as taking vitamin d pill? How many iu d u get from 20m sun?

Actually better. Sun exposure is the way that mother nature intended us to get our vitamin d. It is poorly absorbed by mouth but it is worth getting the blood level of d3 checked. Some people have difficulty in turning cholesterol into vitamin d from sunlight.
Sunshine vitamin D. Sunlight exposure (full body exposure) can produce up to 3, 000 – 20, 000 iu wi sun exposure to the arms and legs for 10-15 minutes. The amount of vitamin d produced depends on the intensity of the uvb in the sun. Darker-skinned individuals may need 5-10 times more exposure than a fair-skinned person. In northern climates sunlight is too weak in winter to do it. http://sunshinevitamin.org/.