Every car guy has his own way of doing things.

That goes for the engineers and marketing guys at big automotive and aftermarket parts manufacturers, too. For example, some fuel pump makers rate their pumps by gallons-per-hour. Others go by pounds-per-hour. Some engines are measured in cubic inches; others are advertised in cubic centimeters.

That’s why we think it’s important to keep a list of measurement conversions handy.

As a public service, we’ve put together this quick guide to common conversions. It includes the basic standard vs. metric stuff, weight conversions for the track, and other assorted automotive-centric conversions you can use. Print it out, along with the 13 Key Formulas You Should Know, and stick it in your toolbox for safe keeping.

Quick Conversions

Ounces vs. Grams: 1 ounce = 28.35 grams
Pounds vs. Grams: 1 pound = 453.6 grams
Pounds vs. Ounces: 1 pound = 16 ounces
Inch vs. Centimeter: 1 inch = 2.540 cm
Inch vs. Millimeter: 1 inch = 25.40 mm
Gallons of Nitro to Pounds: 1 gallon of nitro = 9.5 pounds/1 quart = 2.37 pounds
Gallons of Alcohol to Pounds: 1 gallon of alcohol = 6.6 pounds/1 quart = 1.65 pounds
Gallons of Gasoline to Pounds: 1 gallon of gasoline = 6.2 pounds/1 quart = 1.55 pounds
Gallons of Water to Pounds: 1 gallon of water = 8.3 pounds/1 quart = 2.08 pounds
Gallons of Oil to Pounds: 1 gallon of oil = 7 pounds/1 quart = 1.75 pounds

 

Metric and Standard Conversions

Kilometers to Feet: 1 kilometer = 1,000 meters = 3,280.83 feet
Kilometers to Miles: 1 kilometer = 1,000 meters = .6215 mile
Meters to Inches: 1 meter = 100 centimeters = 39.37 inches
Meters to Yards: 1 meter = 100 centimeters = 1.09 yards
Decimeter to Inches: 1 decimeter = 3.937 inches
Centimeter to Inches: 1 centimeter = .3937 inches
Kilograms to Pounds: kilograms/2.20 = pounds
Pounds vs. Grams: 1 pound = 453.6 grams
Ounces vs. Grams: 1 ounce = 28.35 grams
Grams vs. Millgrams: 1 gram = 1,000 milligrams

 

Engine and Performance

Cubic Inches (CID) = CC ÷ 16.39
Cubic Centimeters (CC) = CID x 16.39
Lbs/hr. (LPH) = divide cc/min by 10.5
Gallons/hr. (GPH) = divide lbs/hr. by 6.0

 

Automotive Plumbing

-AN Size to Fractional Equivalent

-3 AN = 3/16″
-4 AN = 1/4″
-6 AN = 3/8″
-8 AN = 1/2″
-10 AN = 5/8″
-12 AN = 3/4″
-16 AN = 1″
-20 AN = 1-1/4″
-24 AN = 1-1/2″

Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.