# How to Covert Horsepower to Cubic Inches

by Susanne Koenig
engine image by peter Hires Images from Fotolia.com

You may be curious as to the amount of horsepower your engine has in relationship to the size of the engine in cubic inches. The true amount of horsepower in your engine depends greatly on the condition of the engine itself. If any extra tuning, fuel additives or turbo boosting have been implemented, the horsepower will be significantly affected. For a general idea of how much horsepower your engine has in relation to the cubic inches, however, you can implement a simple mathematical formula.

### Step 1

Find the estimated horsepower of your engine. You can do this by checking with the manufacture's website, your owner's manual, or online.

### Step 2

Divide the horsepower by 15, this is a generally-accepted estimate for the number of cubic inches needed to produce one horsepower.

### Step 3

Check online for how the variables of fuel additives, engine modifications and booster kits will affect your horsepower estimate. Each vehicle will give specific results. For modifications and booster kits, read the owner's manuals that came with each particular modification.