Convert Cubic Feet to Cubic Inches

Formula

in³ = ft³ × 1728

Derivation from SI units:

• 1 ft³ = (0.3048 m)³ = 0.028316846592 m³
• 1 in³ = (0.0254 m)³ = 1.6387064 × 10⁻⁵ m³ = 16.387064 cm³
• 1 ft³ = 0.028316846592 m³ ÷ 0.000016387064 m³ per in³ = 1728 in³

Both units are defined exactly, so the factor is exact. Cubic Foot definition: cubic foot; Cubic Inch definition: cubic inch.

Worked examples

1. A reading of 5 ft³ converts to 8640 in³.
   5 ft³ × 1728 = 8640 in³
2. A value of 50 ft³ is 86400 in³.
   50 ft³ × 1728 = 86400 in³

Where it's used

Cubic Feet are used for natural gas billing (ccf, Mcf), while cubic inches appear in US engine displacement (e.g. 350 cubic inches ≈ 5.7 L). Both measure volume (capacity), so the conversion is a fixed factor.

Cubic Foot to other volume units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "cubic foot (ft³)".
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "cubic inch (in³)".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.