Cubic Inches to Gallons Calculator

Enter cubic inches in the calculator below to display the equivalent number of gallons. You can also use the cubic inches to gallons formula for do-it-yourself calculations.

Cubic Inches to Gallons Calculator

There are 231 cubic inches in a U.S. gallon. To convert from cubic inches into gallons, divide your cubic inches value by 231.

Cubic Inches to Gallons Converter

Enter the volume in cubic inches to calculate the equivalent volume in gallons:





Gallons = cubic inches ÷ 231

Reference the table below for common cubic inches to gallons conversions.

Cubic Inches [in3]Gallons [gal]
1 0.00433
20.00866
30.01299
40.01732
50.02165
60.02598
70.03031
80.03464
90.03897
500.21653
1000.43307
1440.62338
2311
337714.6667
5002.16495
10004.3299
10804.68597
10884.71642
1100.47652
12005.15863
12125.21718
500021.6653
777633.8522
10174.41457
1024044.6283
1016444.1098
240010.3798

Difference Between a Cubic Inch and a Gallon

The cubic inch and gallon are volume measurements from the Imperial and United States Customary Systems. The cubic inches represent a 3-d cube in which the length, height, and width all equal one inch. The most common use for cubic inches includes measuring the volume of electric boxes and measuring engine displacement on pre-1980s vehicles.

The gallon is a standard volume measurement used for measuring liquids like milk, water, juice, some dry goods, paint, and gasoline. The United States gallon is the equivalent of 231 cubic inches. The Imperial gallon is 20% bigger, equivalent to 277.42 cubic inches.

How to Convert from Cubic Inches (cu. in.) to Gallons (gal): Example

To determine the number of cubic inches in something, measure the length, width, and height in inches and multiply those numbers by each other. 

If you want to convert 18 x18 x 24 inches into gallons, here’s what to do:

  • Cubic inches = 18 x 18 x 24
  • 7,776 cubic inches = 18 x 18 x24
  • Gallons = 7,776 ÷ 231
  • 33.66 gallons = 7,776 cubic inches

Check out other cubic conversion calculators:


Frequently Asked Questions (FAQ)FAQ

What is the formula for cubic inches to gallons in the U.K.?

The formula for cubic inches to gallons in the U.K. is cubic inches ÷ 277.42. The U.K. gallon is from the British Imperial system and is larger than the U.S. gallon.

How many cubic inches in a gallon of water?

A gallon of water contains 231 cubic inches. 

Does Canada use the U.S. gallon or the Imperial gallon?

Canada uses the imperial gallon. A Canadian gallon is 1.2 times the size of a United States gallon.

How much water is in a cubic inch?

A cubic inch is a 3-D cube with one-inch sides. A single cubic inch is the equivalent of 0.004329 US gallons or 0.0163871 liters.

How do you convert gallons to cubic inches?

To convert gallons to cubic inches, multiply your gallons’ value by 231. For example, 3 gallons equals 693 cubic inches.