Mass per volume density.
Pound per Cubic inches to Pounds per Gallon Converter — lb/in3 to lb/gal
Convert Pound per Cubic inch (lb/in3) to Pound per Gallon (lb/gal) using the exact conversion factor (1 pound per cubic inch = 231 pound per gallon). See the formula, worked examples, conversion table, unit comparison, and common uses.
Pound per Cubic inches to Pounds per Gallon converter
Converter
Density Converter
Convert thousands of mass-per-volume density combinations for science, engineering, agriculture, and fluids.
Context values
Some unit families need one extra value for a physically accurate result.
Mass per volume density.
Result = input x 27679.90471 / 119.8264273.
Density uses kilograms per cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Pound per Cubic inches to Pounds per Gallon
Pound per Cubic inch and Pound per Gallon both measure density — mass per unit volume — a property used to identify materials, check manufacturing quality, and predict whether something floats or sinks. As a fixed reference point, water has a density of exactly 1000 kg/m³ (1 g/cm³, 1 g/mL) at its temperature of maximum density, which is why many density figures in science and engineering are quoted relative to water. Pound per Cubic inch is typically associated with united States, while Pound per Gallon is typically associated with united States (paint, fuel, and industrial liquid density specifications).
Formula
pounds per gallon = pound per cubic inches × 231
This factor comes from each unit's defined relationship to the category's base unit: 1 pound per cubic inch equals 27679.9047102 base units, and 1 pound per gallon equals 119.826427317 base units, so dividing one by the other gives the direct pound per cubic inch-to-pound per gallon factor of 231.
Simple example
1 lb/in3 × 231 = 231 lb/gal
1 pound per cubic inch = 231 pounds per gallon.
Real-world example
1,000 lb/in3 × 231 = 231,000 lb/gal
1,000 pound per cubic inches = 231,000 pounds per gallon.
Conversion table
| Pound per Cubic inch (lb/in3) | Pound per Gallon (lb/gal) |
|---|---|
| 0.1 lb/in3 | 23.1 lb/gal |
| 1 lb/in3 | 231 lb/gal |
| 10 lb/in3 | 2,310 lb/gal |
| 100 lb/in3 | 23,100 lb/gal |
| 1,000 lb/in3 | 231,000 lb/gal |
| 10,000 lb/in3 | 2,310,000 lb/gal |
Reverse conversion: Pound per Gallon to Pound per Cubic inch
231 lb/gal × 0.004329004329 = 1 lb/in3
231 pounds per gallon = 1 pound per cubic inches.
pound per cubic inches = pounds per gallon × 0.004329004329
For a page dedicated to this direction, see Pound per Gallon to Pound per Cubic inch.
Pound per Cubic inch vs. Pound per Gallon
| Aspect | Pound per Cubic inch | Pound per Gallon |
|---|---|---|
| Family | US customary density unit | US customary density unit |
| Typical use | Used in machining and materials engineering, particularly for describing the density of metals, where a smaller volume unit than the cubic foot gives a more convenient figure | US paint and coatings density specifications |
| Where it's used | United States | United States (paint, fuel, and industrial liquid density specifications) |
Understanding the Pound per Cubic inch
Pound per Cubic inch (lb/in3) measures density. A US customary density unit suited to describing dense materials in a small volume. It is classified as a US customary density unit.
Where it's used: United States
Uses of the Pound per Cubic inch today
- Used in machining and materials engineering, particularly for describing the density of metals, where a smaller volume unit than the cubic foot gives a more convenient figure
Understanding the Pound per Gallon
Pound per Gallon (lb/gal) measures density. The US customary unit for liquid density, based on the US gallon (231 cubic inches). It is classified as a US customary density unit.
Where it's used: United States (paint, fuel, and industrial liquid density specifications)
lb/gal vs. lb/ft³. Both are US customary density units; they're related through the real, fixed relationship between the US gallon and the cubic foot (1 cubic foot ≈ 7.48 US gallons), not a round conversion factor.
Uses of the Pound per Gallon today
- US paint and coatings density specifications
- US fuel and petroleum liquid density specs
- Industrial liquid handling and shipping weight calculations
Pound per Cubic inch — sources
- US materials-engineering reference tables — Pounds per cubic inch is a commonly tabulated density unit for metals in US machining and materials references.
Pound per Gallon — sources
- NIST Handbook 44 — General tables of units including US customary density measures.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many pounds per gallon are in 1 pound per cubic inch?
1 pound per cubic inch equals 231 pounds per gallon, using the exact defined conversion factor rather than an estimate.
How do I convert pound per cubic inch to pound per gallon?
Multiply the pound per cubic inch value by 231. The converter above does this instantly to whatever precision you set.
How do I convert pound per gallon back to pound per cubic inch?
Use the reverse factor: 1 pound per gallon equals 0.0043290043 pound per cubic inches. You can also use the swap control in the converter above to flip the direction instantly.
What is a pound per cubic inch?
Pound per Cubic inch (lb/in3) measures density. A US customary density unit suited to describing dense materials in a small volume. It is classified as a US customary density unit.
What is a pound per gallon?
Pound per Gallon (lb/gal) measures density. The US customary unit for liquid density, based on the US gallon (231 cubic inches). It is classified as a US customary density unit.
Is the pound per cubic inch to pound per gallon conversion exact?
Yes. Both pound per cubic inch and pound per gallon are defined by fixed standards rather than physical artifacts, so the factor of 231 used above is exact to as many digits as you choose to display.
What is the difference between lb/gal vs. lb/ft³?
Both are US customary density units; they're related through the real, fixed relationship between the US gallon and the cubic foot (1 cubic foot ≈ 7.48 US gallons), not a round conversion factor.
Where is the pound per cubic inch still used today?
United States