Surfboard Volume
Calculator
A surfboard volume calculator estimates the ideal volume — in litres — for your board based on your weight, surfing ability, and the waves you ride. As a guide, beginners need roughly 100% of their body weight in kg as litres, intermediates around 50–70%, and advanced surfers about 35–40%. Enter your details below for a precise recommendation, plus the exact length, width and thickness Rebel would shape for you.
How surfboard volume is calculated
Volume is a measure of the foam in a board, in litres. It is the single best predictor of how easily a board floats, paddles and catches waves. You calculate it from the board's three dimensions and a shape factor that accounts for how full or foiled the outline is:
ShapeFactor by board type
| Board type | ShapeFactor |
|---|---|
| Shortboard | 0.54 |
| Easy Rider / Fish | 0.56 |
| Hybrid / Funboard | 0.58 |
| Longboard | 0.60 |
Worked example
A 6'0" × 20" × 2½" shortboard. Convert to centimetres (182.9 × 50.8 × 6.35), multiply by the shortboard ShapeFactor of 0.54, divide by 1000:
≈ 31.8 litres
How much volume do I need?
Recommended surfboard volume in litres, by body weight and ability. These are the figures behind Rebel's calculator — find your weight row, then read across to your ability. Values are interpolated for weights in between.
| Weight (kg) | Beginner | Beg → Int | Intermediate | Int → Adv | Advanced |
|---|---|---|---|---|---|
| 36 | 31.9 | 23.9 | 19.9 | 16.7 | 15.9 |
| 39 | 33.1 | 24.4 | 20.7 | 17.4 | 16.6 |
| 41 | 34.3 | 25.7 | 21.4 | 18.0 | 17.1 |
| 43 | 35.3 | 26.5 | 22.1 | 18.6 | 17.7 |
| 45 | 36.3 | 27.2 | 22.6 | 19.1 | 18.1 |
| 50 | 38.9 | 29.2 | 24.3 | 20.4 | 19.5 |
| 54 | 41.4 | 31.0 | 25.9 | 21.7 | 20.7 |
| 59 | 42.5 | 31.8 | 26.5 | 22.3 | 21.2 |
| 64 | 44.4 | 33.3 | 27.8 | 22.3 | 22.2 |
| 66 | 46.0 | 34.5 | 28.8 | 24.2 | 23.0 |
| 68 | 47.6 | 35.7 | 29.8 | 25.0 | 23.8 |
| 70 | 49.2 | 36.9 | 30.8 | 25.8 | 24.6 |
| 73 | 50.8 | 38.1 | 31.8 | 26.7 | 25.4 |
| 76 | 52.4 | 39.3 | 32.7 | 27.5 | 26.2 |
| 77 | 54.0 | 40.5 | 33.7 | 28.3 | 27.0 |
| 79 | 55.5 | 41.7 | 34.7 | 29.2 | 27.8 |
| 82 | 57.1 | 42.9 | 35.7 | 30.0 | 28.6 |
| 84 | 58.7 | 44.0 | 36.7 | 30.8 | 29.4 |
| 86 | 60.3 | 45.2 | 37.7 | 31.7 | 30.2 |
| 88 | 61.9 | 46.4 | 38.7 | 32.5 | 30.9 |
| 91 | 63.5 | 47.6 | 39.7 | 33.3 | 31.8 |
| 95 | 66.7 | 50.0 | 41.7 | 35.0 | 33.3 |
| 100 | 71.8 | 53.9 | 44.9 | 37.7 | 35.9 |
| 104 | 77.2 | 57.9 | 48.2 | 40.5 | 38.6 |
| 109 | 82.7 | 62.0 | 51.7 | 43.4 | 41.4 |
Litres shown are a recommended target; Rebel adjusts for your waves, paddle fitness and age, then shapes to suit. Back to the calculator ↑
Most calculators give a number.
Ours gives a board.
A volume figure on its own is only half the answer. Rebel's calculator reverse-solves the exact length, width and thickness that produce your ideal volume in the shape that suits how you surf — the same starting point Thys Strydom uses at the planer.
Then a human takes over. With more than 20 years and close to 22,000 boards shaped by hand in Jeffreys Bay — a stone's throw from Supertubes — Thys hand-refines every brief into a board built for one surfer. That's the difference between a number and a board you'll ride for years.