Convert Volume from Gallons to Cubic inches (gal to in³)

Gallon to Cubic inch Conversion Formula

Example

Let's convert 5 Gallon (gal) to Cubic inch (in³).

Using the formula:

Therefore, 5 Gallon (gal) is equal to 1155.0053238526646334 Cubic inch (in³).

How many gallons are in one cubic inch? One Cubic inch (in³) contains 0.004328984375 Gallons (gal) — the inverse of the factor above. Multiplying by 231.00106477053292668 takes you from gallons to cubic inches; multiplying by 0.004328984375 brings you back.

Put in words: one gallon equals 231.00106477053292668 cubic inches, so the gallon is the larger unit of this pair. Converting between them never changes the amount of volume being measured — only the size of the unit you count it in.

What is a Gallon (gal)?

A gallon (gal) is a unit of volume, most commonly associated with the imperial and US customary systems of measurement.

It is equal to 128 Fluid Ounces (fl-oz).

What's the Difference Between a US Gallon and an Imperial Gallon?

A common point of confusion is the difference between the US gallon and the imperial gallon (used in the UK and other Commonwealth nations).

They are not the same size!

• The US Gallon is smaller, defined as 231 cubic inches, which is approximately 3.785 liters.
• The Imperial Gallon is larger, equivalent to about 4.546 liters.

This difference stems from historical definitions that were standardized differently in the US and Britain during the 18th and 19th centuries.

So, if you're comparing fuel efficiency, remember that "miles per gallon" ratings are based on different-sized gallons!

Where Does the Word "Gallon" Come From?

The word "gallon" has a rich history, tracing its roots back through several languages.

It originates from the Old Northern French word galon, which referred to a liquid measure.

This term is believed to have originated from the Gallo-Roman word gallēta, meaning a "pail" or "bucket." The ultimate origin likely goes back to a Celtic word, highlighting the unit's long-standing use in European trade and daily life for centuries.

What is a "Dry" Gallon?

While we typically associate the gallon with liquids, there is also a US dry gallon.

This unit, not commonly used today, is equivalent to one-eighth of a bushel, or about 4.405 liters. It was historically used to measure dry goods such as grain or fruit.

This is also why the famous "10-gallon hat" is a misnomer; its name doesn't refer to its volume.

Instead, it is thought to originate from the Spanish word galón, meaning "braid," which refers to the braided band on the hat.

What Is a Cubic Inch (in³)?

A cubic inch (in³) is a unit of volume in the imperial and US customary systems of measurement.

One cubic inch is equal to about 0.554 fluid ounces (fl oz).

How Many Cubic Centimeters Are in a Cubic Inch?

One cubic inch is precisely equal to 16.387064 cubic centimeters (cm³).

This exact conversion is legally defined and crucial in fields like engineering, science, and international manufacturing, where precision is paramount.

It enables the direct and accurate translation of volume measurements between the imperial system (common in the US) and the metric system, which is used worldwide.

Why Is Engine Size Measured in Cubic Inches?

The cubic inch is famously used to measure an engine's displacement (often abbreviated as CID), especially in American automotive history.

Engine displacement refers to the total volume of air and fuel that an engine's cylinders can move through in one cycle.

A higher CID, such as in the classic "454" (454 in³) V8 engines, typically meant more potential for power and torque, defining the era of American muscle cars.

What Does a Cubic Inch Look Like in Real Life?

To visualize a cubic inch, think of a small, common object.

A standard six-sided die used in board games is a perfect example, having a volume very close to one cubic inch.

A small sugar cube or a standard marble also provides a good real-world approximation of this unit of volume, making it easier to conceptualize its size beyond abstract numbers.

Gallon to Cubic inch Conversion Table

Here are some quick reference conversions from Gallon (gal) to Cubic inch (in³):