The concept of surfboard volume is increasingly popular, although it has been used in windsurfing for a long time. Buoyancy is, in fact, a critical factor when it comes paddling and gliding.
For several decades, shapers wrote three main specs on the back of their surfboards. They were length, width and thickness. Volume, in liters, was never there.
Recently, former pro surfer John Whitney Guild proposed the inclusion of the volume ratio to rider weight in our surfboard knowledge, so that surfers could easily choose the best surfboard for themselves.
Knowing that two surfers with the same weight and distinct experience levels will paddle for a wave differently, the floatation needs should be adapted wisely. In other cases, we might need a bigger board for catching mushy waves.
The intermediate/advanced surfer on a shortboard will require between 33-35% of his body weight in board volume. For example, a surfer weighing 154 lbs (70 kilograms) should get a 24-liter surfboard.
Beginners in the art of surfing will easily learn how to pop up on a surfboard with higher flotation ratios. This means that the most suitable surfboards for learning how to surf will have more volume, that is to say more liters, bigger surfboards.
Having in mind that one liter floats one kilogram of weight, Whitney Guild created a volumetric table system named "Guild Factor." This surfing scale allows us to pick the right surfboard for our skills and wave conditions, but it can also be used for longboards and stand up paddle boards.
So, what are the most common "Guild Factor" ratios?
Formula: Surfer's Weight in Kilograms (Kg) X Guild Factor (GF) for Skill Level = Liters of Surfboard Volume
Advanced/Pro Surfers: 0.34-0.36 (GF)
Intermediate/Advanced Surfers: 0.36-0.38 (GF)
Intermediate/Older Surfers: 0.38-0.42 (GF)
Weekend Warriors/Casual Surfers: 0.43-0.49+ (GF)
Beginner Surfers: 0.50+ (GF)