Gallons to Cubic Inches Conversion

Need to convert gallons to cubic inches? Whether you’re working with fluid capacities, container sizes, or engine displacements, this guide helps you quickly and accurately convert between U.S. gallons and cubic inches.

What Is a U.S. Gallon?

The U.S. gallon is a standard unit of volume used in the U.S. customary system. It is defined as exactly 231 cubic inches. It is also equal to 3.785 liters in the metric system. The gallon is subdivided in this way:

• 1 gallon = 4 quarts
• 1 quart = 2 pints
• 1 pint = 2 cups
• 1 cup = 2 gills
• 1 U.S. fluid ounce = 1/128 of a gallon

Note: The U.S. gallon is different from the imperial gallon used in the UK and other Commonwealth countries, which is larger (4.54609 liters).

Origin of the Gallon

The word “gallon” comes from Old Northern French “galon.” Gallons were historically used in the U.K. to measure beer, ale, and wine, with several variations emerging over time, including the wine gallon and ale gallon.

Current Usage

In the U.S., gallons are commonly used to measure fuel, beverages like milk and juice, and liquid cleaning products. It’s also a unit of choice for fuel efficiency (miles per gallon).

What Is a Cubic Inch?

A cubic inch (in³) is a unit of volume based on the inch, with dimensions of 1 inch × 1 inch × 1 inch. It equals approximately 16.387 cubic centimeters (cm³).

Historical Background

The cubic inch originates from the traditional inch, which was standardized in 1959 to exactly 2.54 centimeters. The cubic inch, therefore, became precisely 16.387064 cm³.

Modern-Day Use

While less common in everyday applications, cubic inches are still used in automotive and aerospace industries, particularly in the U.S. Engine displacements are frequently labeled in cubic inches (e.g., 350 in³). In the UK, older car models may also reference this unit.

Gallons to Cubic Inches Conversion Chart

Gallons (US)	Cubic Inches (in³)
0.01 gal	2.31 in³
0.1 gal	23.1 in³
1 gal	231 in³
2 gal	462 in³
3 gal	693 in³
5 gal	1,155 in³
10 gal	2,310 in³
20 gal	4,620 in³
50 gal	11,550 in³
100 gal	23,100 in³
1000 gal	231,000 in³

Conversion Formula: Gallons to Cubic Inches

To convert gallons to cubic inches, multiply the volume in gallons by 231:

Cubic Inches = Gallons × 231

Example

Convert 15 U.S. gallons to cubic inches:

15 gal × 231 = 3,465 in³

Read more guideline here:

• U.S. National Institute of Standards and Technology (NIST) – Metric Conversion Guidelines
• Engineering Toolbox – Volume Unit Conversion Reference

Related Tools

• Gallon to Liter
• Cubic Inches to Gallons
• Gallons to Cubic Inches