Hull Speed Calculator
Offline water sports & boating calculator
Hull Speed Calculator: Find Your Boat’s Sweet Spot
Calculate your boat’s optimal cruising speed in seconds, without complicated math.
If you’ve ever wondered how fast your boat can comfortably cruise, you’re in the right place. The Hull Speed Calculator helps you figure out the maximum efficient speed for displacement hulls – just enter your boat’s waterline length and get results instantly. For a deeper explanation of the idea behind hull speed and why it matters for everyday boating, you can also read this practical guide to hull speed and boat performance.
What’s Hull Speed All About?
Hull speed is your boat’s natural cruising limit. As a displacement boat moves through water, it creates waves. At a certain speed, these waves resist motion, making it harder to go faster. This “magic number” happens when the wavelength matches your boat’s waterline length.
The classic formula sailors use is:
Hull Speed (knots) = 1.34 × √(Waterline Length in feet)
Reliable for everything from small sailboats to cruising yachts.
Why Bother With a Calculator?
- Quickly calculate hull speed without manual math
- Works on your phone or tablet
- Perfect for dock-side discussions about performance
- Handles unit conversions automatically
What Makes It Handy
- Get your answer in seconds
- Works offline
- Choose your preferred units
- Easy to use on any device
- Great for quick performance comparisons
Units? We’ve Got You Covered
Measuring Your Waterline: Enter your boat’s waterline length in:
- Centimeters (cm)
- Meters (m)
- Inches (in)
- Feet (ft)
- Yards (yd)
The calculator handles all conversions behind the scenes.
Speed Results Your Way: Display results in:
- Knots (kn)
- Kilometers per hour (km/h)
- Meters per second (m/s)
- Feet per second (ft/s)
- Miles per hour (mph)
How It Works
- Type in your boat’s waterline length
- Pick your measurement unit
- Choose the speed unit for results
- Click “Calculate” – instant results!
Everything runs in your browser, fast, private, and offline-friendly.
Quick Example
Boat with a 25-foot waterline:
- √25 = 5
- Multiply by 1.34 = 6.7 knots
The calculator instantly converts this into mph, km/h, or any other unit you choose.
Who Finds This Useful?
- Sailors checking optimal cruising speed
- Boat owners maximizing fuel efficiency
- Water sports fans comparing boats
- Students learning boat design
- Anyone curious about how boats work
Built for Real-World Use
Designed to be practical: no clutter, fast loading, offline-ready, accurate every time. Perfect for dockside, marina, or out on the water.
FAQs
- Is hull speed an absolute limit? Not exactly. Displacement boats can go faster but need more power. Planing boats behave differently.
- Do different hull shapes matter? Yes. A racing yacht and a cruiser with the same waterline feel different, but the calculator gives a solid baseline.
- Any cost to use this? Nope, it’s completely free.