Conversion Formula
$$SG = \frac{\rho_{\text{lb/gal}}}{8.3454}$$
Divide lb/gal by 8.3454 (density of water in lb/gal) to get specific gravity.
lb/gal to SG Conversion Table
| Pound per US Gallon (lb/gal) | Specific Gravity (SG) |
|---|---|
| 0.1 | 0.0119826 |
| 0.5 | 0.0599132 |
| 1 | 0.119826 |
| 2 | 0.239653 |
| 5 | 0.599132 |
| 10 | 1.19826 |
| 25 | 2.99566 |
| 50 | 5.99132 |
| 100 | 11.9826 |
| 250 | 29.9566 |
| 500 | 59.9132 |
| 1,000 | 119.826 |
lb/gal to SG in Engineering
Density conversions are critical for fluid mechanics, material selection, concrete mix design, and petroleum engineering. Specific gravity (relative to water at 4°C) is commonly used as a dimensionless density ratio across all disciplines.
Pound per US Gallon: Common for liquid densities in US practice. Water = 8.345 lb/gal. Used in petroleum and chemical processing.
Specific Gravity: Dimensionless ratio of density to water at 4°C (1000 kg/m³). SG = 1.0 for water. Universal engineering reference.