Convert Cubic Centimeters to US Gallons

Formula

gal (US) = cm³ × 0.0002641720523581

or gal (US) = cm³ ÷ 3785.411784

Derivation from SI units:

• 1 cm³ = (0.01 m)³ = 10⁻⁶ m³ = 1 mL
• 1 US gal = 231 in³ = 231 × (0.0254 m)³ = 0.003785411784 m³
• 1 cm³ = 0.000001 m³ ÷ 0.003785411784 m³ per gal (US) = 0.0002641720523581 gal (US)

Both units are defined exactly, so the factor is exact. Cubic Centimeter definition: cubic centimeter; US Gallon definition: US gallon.

Worked examples

1. A reading of 10 cm³ converts to 0.002641720524 gal (US).
   10 cm³ × 0.0002641720524 = 0.002641720524 gal (US)
2. A value of 500 cm³ is 0.1320860262 gal (US).
   500 cm³ × 0.0002641720524 = 0.1320860262 gal (US)

Where it's used

Cubic Centimeters are used for engine displacement (e.g. 125 cc, 1600 cc), while US gallons appear in fuel, water and chemical volumes in the US. Both measure volume (capacity), so the conversion is a fixed factor.

Cubic Centimeter to other volume units

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 2 with SI prefix centi.
• 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, "gallon [U.S.] (gal)".
• NIST Handbook 44, Appendix C: General Tables of Units of Measurement, National Institute of Standards and Technology , Appendix C.

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