Windsurfing gear is sized to the rider and the conditions: heavier sailors need more sail and floating volume, while experienced riders use smaller boards that sink when stationary but are fast and agile when planing.
How to use the Windsurfing Sail and Board Size Calculator
- Sailor weight
- Wind speed
- Your level
Rough guidelines only – check local conditions and ask your local school. Everything is calculated in your browser.
How it works
Enter your weight and the wind speed, and choose your level for the board volume.
Tips
- Check local conditions and safety rules before going out.
- Start with conservative equipment choices and adjust with experience.
- Every field has its own unit menu.
- Everything is calculated in your browser.
Common mistakes to avoid
- Using estimates instead of a proper check in the water.
- Mixing feet and metres, or knots and km/h.
- Overestimating your skill in strong wind.
Inputs explained
| Field | What to enter |
|---|---|
| Sailor weight | Units: kg, lb |
| Wind speed | Units: kn, km/h, mph, m/s |
| Your level | Choose one: Complete beginner (+130 L), Intermediate / cruising (+100 L), First short board (+60 L), Comfortable uphauling (+30 L) … |
What each result means
- Wind = [Wind speed]÷0.514444
- Recommended sail size = [Sailor weight]×1.34÷([Wind speed]÷0.514444)
- Recommended board volume = [Sailor weight] + [Your level]
- Typical fin length = [Sailor weight]×1.34÷([Wind speed]÷0.514444)×5.5
Example values
How the main result changes when Sailor weight changes and everything else stays at the example values above:
| Sailor weight (kg) | Recommended sail size (m²) |
|---|---|
| 37.5 | 2.8 |
| 56.25 | 4.2 |
| 75 | 5.6 |
| 93.75 | 7 |
| 112.5 | 8.4 |
| 150 | 11.2 |
Formula
Sail (m²) = weight (kg) × 1.34 ÷ wind (knots) · Board volume (L) = weight (kg) + skill bonus (beginner +130, intermediate +100, first short board +60, … sinker 0 or less)
Worked example
Inputs — Sailor weight: 75 kg; Wind speed: 18 kn; Your level: Intermediate / cruising (+100 L).
Results — Wind = 18 kn; Recommended sail size = 5.6 m²; Recommended board volume = 175 L; Typical fin length = 31 cm.
Key terms
- Sinker
- Board with less volume than the sailor's weight.
Frequently asked questions
What sail size for beginners?
Small sails (3–5 m²) in light wind while learning.
What board volume floats me?
Roughly your weight in kg as litres plus 20–30 L to uphaul.
How much wind for planing?
Usually 12–15 knots with the right gear.
Does fin size matter?
Yes – bigger sails need longer fins for grip.