Convert Cubic Inch to Cup (in³ → cup)

Converting cubic inches to cups is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in cubic inches

   Start with the number of cubic inches (in³) you want to convert.
2. 2
   Multiply by 0.068279

   The conversion factor from in³ to cup is 0.068279. Multiply your value by this number.
3. 3
   Read the result in cups

   The result is your value in cups (cup).

Multiply the value in cubic inches by 0.068279. For the reverse direction, multiply by 14.645699.

• ✓1 in³ = 16.387 cm³ exactly.
• ✓To convert cubic inches to litres, divide by 61.02.
• ✓US automotive ads today quote both cu in and L for classic cars.

• ✗Confusing in³ with in² or linear inches.
• ✗Using 16 instead of 16.387 on precision machining.
• ✗Assuming modern European engines are marked in cu in — they are always in L or cc.

What is the Cubic Inch?

The cubic inch equals exactly 16.387064 cubic centimeters and is the traditional American unit for engine displacement and small-volume manufacturing measurements. Classic American muscle cars were famously identified by their cubic-inch engine size: the Ford 'Boss 429' had a 429-cubic-inch (7.0-liter) V8, and the Chevrolet 'Big Block 454' was 7.4 liters. Modern American automakers have transitioned mostly to liter-based naming (e.g., 'Hemi 5.7'), but the cubic inch persists in vintage car culture and aviation engines. It is also used for printer-paper coverage and industrial tolerances. The cubic inch relates to the cubic foot (1,728 in³ = 1 ft³), the cubic centimeter (1 in³ ≈ 16.39 cm³), the milliliter (1 in³ ≈ 16.39 mL), and the US fluid ounce (1 fl oz ≈ 1.805 in³).

• Classic US car engine displacement
• Firearms chamber and cartridge specs
• Some US machining and mould design

What is the Cup?

The US cup equals exactly 240 milliliters (a definition standardized for nutrition labeling; the legal volume for cooking is 236.588 mL, derived from 8 US fluid ounces). The cup is the cornerstone of American baking and home cooking, with virtually every US recipe using volume measurements rather than the weight measurements common in European cooking. Standard measuring-cup sets include 1, ½, ⅓, and ¼ cup sizes. The metric cup (used in Australia, New Zealand, and increasingly in international recipes) is exactly 250 mL — slightly larger than the US cup. The cup relates to the gallon (16 cups = 1 gal), the pint (2 cups = 1 pt), the fluid ounce (8 fl oz = 1 cup), the tablespoon (16 tbsp = 1 cup), and the milliliter (1 cup ≈ 237–240 mL). American baking-by-volume is sometimes criticized internationally for its variability compared to gram-based measurements.

• US cooking and baking recipes
• Cereal and beverage serving sizes in US nutrition labels
• Volume estimation when no scale is available