The length range of electric bass straps is between 38 and 56 inches. Most bassists prefer a strap length of 42 to 48 inches.
Double Bass Strap
The strap’s length should measure between 36 and 50 inches. Generally, double bass straps come with adjustable hardware, so finding a length that fits can be achieved through minor adjustments.
Measure for the correct length
1. Stand straight and hold the bass in playing position.
2. Adjust the strap so the bottom of the bass body rests approximately midway between your waist and knees.