Marine Tank Capacity Calculator

Calculate fuel, water, and holding tank volumes and weights for marine applications.

Tank Length

Tank Width / Diameter

Tank Height

Tank Shape

Fill Percentage

Fluid Type

Tab to move between fields

Usable Capacity

80.8 gal

≈ 16 buckets

Fluid Weight

574 lbs

≈ 3 adults

Usable Capacity (L)305.8 L

Fluid Weight (kg)260 kg

Total Volume12 ft³

Fuel Range (at 5 GPH)16.2 hours

How to Use This Calculator

Enter tank length, width/diameter, and height in feet.
Select the tank shape: rectangular, cylindrical, or oval/elliptical.
Set the fill percentage and choose the fluid type (diesel, gasoline, fresh water, or black water).
Review usable capacity in gallons and liters, and the weight of the fluid for stability planning.
Use the fluid weight output when calculating vessel trim and stability changes from fuel consumption.

How the result changes with Tank Length

Tank Length: Internal length of the tank.
Tank Width / Diameter: Internal width (rectangular) or diameter (cylindrical).
Tank Height: Internal height (ignored for cylindrical tanks).
Tank Shape: Cross-sectional shape of the tank.
Fill Percentage: Typical max fill is 90% to allow for expansion.
Fluid Type: Fluid type determines weight calculation.

Identify Input Parameters
4 parameters
Tank Length = 4, Tank Width / Diameter = 2, Tank Height = 1.5, Tank Shape = 0 = 6 input(s) provided
Calculate Usable Capacity
Usable Capacity
80.8 = 80.8
Calculate Fluid Weight
Fluid Weight
574 = 574
Calculate Usable Capacity
Usable Capacity
305.8 = 305.8
Calculate Fluid Weight
Fluid Weight
260 = 260