Mass per volume density.
Pounds per Gallon to Grain per Cubic inches Converter — lb/gal to gr/in3
Convert Pound per Gallon (lb/gal) to Grain per Cubic inch (gr/in3) using the exact conversion factor (1 pound per gallon = 30.3030303 grain per cubic inch). See the formula, worked examples, conversion table, and common uses.
Pounds per Gallon to Grain per Cubic inches 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 119.8264273 / 3.954272101.
Density uses kilograms per cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Pounds per Gallon to Grain per Cubic inches
Pound per Gallon and Grain per Cubic inch 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 Gallon is most often used for us paint and coatings density specifications.
Formula
grain per cubic inches = pounds per gallon × 30.303030303
This factor comes from each unit's defined relationship to the category's base unit: 1 pound per gallon equals 119.826427317 base units, and 1 grain per cubic inch equals 3.95427210146 base units, so dividing one by the other gives the direct pound per gallon-to-grain per cubic inch factor of 30.303030303.
Simple example
1 lb/gal × 30.3030303 = 30.3030303 gr/in3
1 pound per gallon = 30.3030303 grain per cubic inches.
Real-world example
1,000 lb/gal × 30.3030303 = 30,303.0303 gr/in3
1,000 pounds per gallon = 30,303.0303 grain per cubic inches.
Conversion table
| Pound per Gallon (lb/gal) | Grain per Cubic inch (gr/in3) |
|---|---|
| 0.1 lb/gal | 3.03030303 gr/in3 |
| 1 lb/gal | 30.3030303 gr/in3 |
| 10 lb/gal | 303.030303 gr/in3 |
| 100 lb/gal | 3,030.30303 gr/in3 |
| 1,000 lb/gal | 30,303.0303 gr/in3 |
| 10,000 lb/gal | 303,030.303 gr/in3 |
Reverse conversion: Grain per Cubic inch to Pound per Gallon
30.3030303 gr/in3 × 0.033 = 0.9999999999 lb/gal
30.3030303 grain per cubic inches = 0.9999999999 pounds per gallon.
pounds per gallon = grain per cubic inches × 0.033
For a page dedicated to this direction, see Grain per Cubic inch to Pound per Gallon.
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
Understanding the Grain per Cubic inch (gr/in3)
Mass per volume density.
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 grain per cubic inches are in 1 pound per gallon?
1 pound per gallon equals 30.3030303 grain per cubic inches, using the exact defined conversion factor rather than an estimate.
How do I convert pound per gallon to grain per cubic inch?
Multiply the pound per gallon value by 30.3030303. The converter above does this instantly to whatever precision you set.
How do I convert grain per cubic inch back to pound per gallon?
Use the reverse factor: 1 grain per cubic inch equals 0.033 pounds per gallon. You can also use the swap control in the converter above to flip the direction instantly.
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.
What is a grain per cubic inch?
Grain per Cubic inch (gr/in3) is a unit of density.
Is the pound per gallon to grain per cubic inch conversion exact?
Yes. Both pound per gallon and grain per cubic inch are defined by fixed standards rather than physical artifacts, so the factor of 30.3030303 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 gallon still used today?
United States (paint, fuel, and industrial liquid density specifications)