Fuel Tank Capacity Calculator 🛢️
Calculate your boat's fuel tank volume in US gallons and liters. Supports rectangular and cylindrical tank shapes. Enter dimensions in inches.
How to Use the Fuel Tank Capacity Calculator
Select your tank shape (rectangular or cylindrical), enter inside dimensions in inches, and the calculator computes volume in US gallons and liters. 1 US gallon = 231 cubic inches.
Rectangular: Volume = L × W × H. Cylindrical (horizontal): Volume = π × (D/2)² × L. Measure inside dimensions for accuracy.
Leave 5–10% ullage (air space) for fuel expansion — never fill a marine fuel tank 100% full. Overfilling causes fuel to overflow through the vent, creating fire and environmental hazards.
FAQ
How do I calculate boat fuel tank capacity?
Rectangular: Volume (cu in) = L × W × H, then divide by 231 for US gallons. Cylindrical: Volume (cu in) = π × (D/2)² × Length, then divide by 231. All measurements in inches. 1 US gallon = 231 cubic inches.
How full should I fill a marine fuel tank?
Fill marine fuel tanks to 90–95%, leaving 5–10% ullage for thermal expansion. Overfilling causes fuel to overflow through the vent, creating fire and environmental hazards. Use a slow fill rate near the top.
How do I convert cubic inches to gallons?
Divide cubic inches by 231. Example: a 24" × 12" × 10" tank = 2880 cu in ÷ 231 = 12.5 US gallons. Multiply gallons by 3.785 to convert to liters.
What is the typical fuel tank size for a recreational boat?
Small runabouts (16–20 ft): 15–40 gallons. Mid-size boats (20–25 ft): 50–100 gallons. Larger cruisers (25–35 ft): 100–300 gallons. Center consoles vary widely. Check your owner's manual for the exact capacity.