Boat Displacement Calculator

Estimate your boat's displacement, waterline area, and theoretical hull speed from hull dimensions and type.

Inputs

Waterline Length

Beam (Width)

Draft

Hull Type

Tab to move between fields

Results

Displacement

36,960 lbs

≈ 11 small cars

Hull Speed

7.34 knots

Displacement16.5 long tons

Waterline Area210 sq ft

Displaced Volume577.5 cu ft

D/L Ratio611

Classification (1=ultra-light, 4=heavy)4

How to Use This Calculator

Enter the waterline length (LWL), beam, and draft of your boat in feet.
Select the hull type: displacement cruiser, semi-displacement, or planing.
Review the displacement in pounds and long tons — important for loading calculations.
Check hull speed (knots) to understand your boat's theoretical maximum speed under power.
Use the D/L ratio and hull classification to compare against similar vessels.

How the result changes with Waterline Length

Waterline Length	Displacement	Hull Speed
27	33,264 lbs	6.96 knots
75	92,400 lbs	11.6 knots
133	163,856 lbs	15.45 knots
181	222,992 lbs	18.03 knots

What each input means

Waterline Length: Length at the waterline (LWL) in feet.
Beam (Width): Maximum beam (width) of the hull in feet.
Draft: Depth of hull below the waterline in feet.
Hull Type: Hull design type affects displacement estimates.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Waterline Length = 30, Beam (Width) = 10, Draft = 3.5, Hull Type = 1 = 4 input(s) provided
Calculate Displacement
Displacement
36960 = 36960
Calculate Hull Speed
Hull Speed
7.34 = 7.34
Calculate Displacement
Displacement
16.5 = 16.5
Calculate Waterline Area
Waterline Area
210 = 210

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Marine & Boating

Marine Fuel Consumption Calculator

Calculate fuel needed, trip time, cost, and range for your boat based on engine specs, speed, and distance.

Marine & Boating

Anchor Line (Rode) Calculator

Calculate the proper anchor line scope, chain length, and rope length based on water depth and conditions.

Naval Architecture

Hull Speed Calculator

Calculate theoretical hull speed from waterline length using the speed-length ratio formula.

Water Sports & Diving

Sail Area Calculator

Determine the optimal sail area for your boat based on displacement, hull length, and wind conditions. Includes sail area to displacement ratio.