cu in

Units & Measurements abbreviation · US Customary and Imperial Unit

cu in
Stands forCubic inch
CategoriesUnits & Measurements

cu in stands for Cubic inch, a US customary and imperial unit abbreviation.

Volume of a cube one inch on each side, about 16.39 cubic centimeters. The US gallon is legally defined as exactly 231 cu in, and American engine sizes were traditionally quoted in cubic inches.

Example: The classic small-block V8 displaces 350 cu in, about 5.7 liters.

Usage notes

Also written in³ or ci. The 231-cubic-inch gallon dates from the English wine gallon of Queen Anne's era in 1707, which the US kept after Britain adopted the larger imperial gallon in 1824. Luggage and case manufacturers sometimes list capacity in cubic inches.

More US customary and imperial unit abbreviations

  • bbl – Barrel (oil)
  • bd ft – Board foot
  • bu – Bushel
  • CCF – Hundred cubic feet
  • ch – Chain
  • cu ft – Cubic foot
  • cu yd – Cubic yard
  • cwt – Hundredweight
  • dr – Dram
  • dwt – Pennyweight
  • fl oz – Fluid ounce
  • ft – Foot

See all 43 US customary and imperial unit abbreviations →

Edited by the AbbreviationList.com team. Spotted an error or a missing meaning? Contact us.