Work out shadow length instantly with clear inputs, formula shown and shareable results.
Shadow length is height divided by the tangent of solar elevation. At 30 degrees a 10 m object casts a 17.3 m shadow; at 45 degrees the shadow equals the height exactly. The relationship is how Eratosthenes measured Earth's circumference and how solar access and overshadowing are assessed in planning.
Shadow length
length = height / tan(solar elevation)
Inverse
height = shadow length x tan(solar elevation)
45 degrees, where the tangent is one. Below that shadows exceed the height and grow rapidly.
To check overshadowing at the winter solstice, when the sun is lowest and shadows longest - the worst case for solar access.