Windsurfing Calculator

Sail size depends primarily on your body weight and the wind speed you're sailing in. A lighter rider needs a larger sail in light winds to generate enough power, while a heavier rider needs a bigger sail overall. As a general rule, divide a weight-adjusted power factor by the wind speed squared to arrive at an appropriate sail area in m².

Board volume (in liters) should be matched to your weight and skill level. Beginners typically need a board volume at least 50–100 L more than their body weight in kg to ensure stability and easy uphauling. As you progress to planing and shortboard riding, you can reduce volume significantly — advanced riders often use boards equal to or even less than their body weight in liters.

The fin provides lateral resistance and lift, controlling how the board tracks and how easily it planes. A fin that's too small won't generate enough lift and the board will slip sideways; too large and it becomes hard to control at speed. Fin size is closely tied to sail size — a larger sail needs a bigger fin to handle the extra drive.

Yes! Enter your known sail size in the optional 'Known Sail Size' field and the calculator will output the ideal wind speed range — including underpowered and overpowered thresholds — for that specific sail and your body weight.

You can input wind speed in knots, km/h, mph, or m/s. The calculator converts everything internally to knots for the formulas and displays results in knots by default. Use the Wind Speed Unit selector to match whatever source you're reading (weather app, forecast site, anemometer).

Skill level influences board volume recommendations. Beginners benefit from higher-volume, more stable boards, while intermediate and advanced riders can handle lower-volume boards that are more responsive and performance-oriented. Sail size recommendations remain primarily weight- and wind-driven regardless of skill level.

A sinker board has a volume lower than the rider's body weight in liters, meaning it literally sinks when you stand still. These boards are designed for advanced riders who are always moving fast enough to generate hydrodynamic lift. They offer high performance but require strong wind and solid planing skills to use effectively.

The beginner sail size recommendation prioritizes controllability and stability over maximum power. Beginners are advised to start with slightly smaller sails than the formula suggests so they can focus on balance and basic maneuvers without being overpowered. As your technique improves, you can move toward the calculated optimal size.