Sail Area to Displacement Ratio Calculator
Fill in the values and the answer updates as you type.
How the Sail Area to Displacement Ratio Calculator works
Ratio = sail area (sq ft) ÷ (displacement volume in cubic feet)^(2/3), and displacement volume = displacement in pounds ÷ 64, which is the weight of a cubic foot of seawater. Use the sail area of the mainsail plus the foretriangle, not an overlapping genoa. The ratio compares engine power to weight, so it shows how well a boat moves in light air. The bands in the result are rough guides. Real performance also depends on hull shape, keel, and rig. Example: with Sail area (mainsail plus 100% foretriangle) 650 sq ft, and Displacement 14000 lb, the result is Sail area to displacement ratio = 17.9; Displacement volume (cu ft) = 219; Sail area (sq m) = 60.4.
Inputs and results
The Sail Area to Displacement Ratio Calculator takes 2 inputs and gives 4 results.
What you enter
- Sail area (mainsail plus 100% foretriangle) (sq ft) — starts at 650.
- Displacement (lb) — starts at 14000.
What you get
- Sail area to displacement ratio
- Displacement volume (cu ft)
- Sail area (sq m)
- What this means
Sail Area to Displacement Ratio Calculator FAQ
How do I use the Sail Area to Displacement Ratio Calculator?
Enter sail area (mainsail plus 100% foretriangle) and displacement in the fields, then read sail area to displacement ratio, displacement volume (cu ft), sail area (sq m) and what this means in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Sail Area to Displacement Ratio Calculator calculate?
Rate how powered-up a sailboat is from sail area and weight. It returns sail area to displacement ratio, displacement volume (cu ft), sail area (sq m) and what this means from the 2 values you provide.
What values does the Sail Area to Displacement Ratio Calculator start with?
It opens with sail area (mainsail plus 100% foretriangle) 650 sq ft and displacement 14000 lb so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Sail Area to Displacement Ratio Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Sail Area to Displacement Ratio Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.