The B-type of DNA double helix described by Watson and Crick is the most predominant type under physiological conditions.

Adjacent nucleotides in each chain are rotated by 34.60 relative to each other. Double helix completes one turn approximately every 10.4 base pairs.

A single turn of a double helix spans a distance of 3.4 nm. Therefore, a single base pair increases the length of a double helix by 0.33 nm.

Diametre of the double helix is 2.37 nm.

When the B-DNA crystals are dried and the salt content of the crystal is lowered, B-DNA becomes the short and stubby molecule of A-DNA.