Convert Pounds per Gallon to Pounds per Cubic Foot

Formula

lb/ft³ = lb/gal × 7.480519480519

Derivation from SI units:

• 1 lb/gal = 0.45359237 kg ÷ 0.003785411784 m³ = 119.8264273 kg/m³
• 1 lb/ft³ = 0.45359237 kg ÷ 0.028316846592 m³ = 16.018463374 kg/m³
• 1 lb/gal = 119.8264273169 kg/m³ ÷ 16.01846337396 kg/m³ per lb/ft³ = 7.480519480519 lb/ft³

Both units are defined exactly, so the factor is exact. Pound per Gallon definition: pound per gallon; Pound per Cubic Foot definition: pound per cubic foot.

Worked examples

1. A reading of 7.1 lb/gal converts to 53.11168831 lb/ft³.
   7.1 lb/gal × 7.480519481 = 53.11168831 lb/ft³
2. A value of 10 lb/gal is 74.80519481 lb/ft³.
   10 lb/gal × 7.480519481 = 74.80519481 lb/ft³

Where it's used

Pounds per Gallon are used for drilling-mud weight in the oil and gas industry (ppg), while pounds per cubic foot appear in concrete, soil and aggregate densities (normal concrete ≈ 145–150 pcf). Both measure density (mass per unit volume) and mass concentration, so the conversion is a fixed factor.

Pound per Gallon to other density 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, "pound per gallon (U.S.)".
• 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, "pound per cubic foot (lb/ft³)".

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