Mass per volume density.
Pound per Cubic inches to Grains per Cubic Millimeter Converter — lb/in3 to gr/mm3
Convert Pound per Cubic inch (lb/in3) to Grain per Cubic Millimeter (gr/mm3) using the exact conversion factor (1 pound per cubic inch = 0.4271662087 grain per cubic millimeter). See the formula, worked examples, conversion table, and common uses.
Pound per Cubic inches to Grains per Cubic Millimeter 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 / 64798.91.
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 Grains per Cubic Millimeter
Pound per Cubic inch and Grain per Cubic Millimeter 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 most often used for 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.
Formula
grains per cubic millimeter = pound per cubic inches × 0.427166208663
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 grain per cubic millimeter equals 64798.91 base units, so dividing one by the other gives the direct pound per cubic inch-to-grain per cubic millimeter factor of 0.427166208663.
Simple example
1 lb/in3 × 0.4271662087 = 0.4271662087 gr/mm3
1 pound per cubic inch = 0.4271662087 grains per cubic millimeter.
Real-world example
1,000 lb/in3 × 0.4271662087 = 427.1662087 gr/mm3
1,000 pound per cubic inches = 427.1662087 grains per cubic millimeter.
Conversion table
| Pound per Cubic inch (lb/in3) | Grain per Cubic Millimeter (gr/mm3) |
|---|---|
| 0.1 lb/in3 | 0.0427166209 gr/mm3 |
| 1 lb/in3 | 0.4271662087 gr/mm3 |
| 10 lb/in3 | 4.271662087 gr/mm3 |
| 100 lb/in3 | 42.71662087 gr/mm3 |
| 1,000 lb/in3 | 427.1662087 gr/mm3 |
| 10,000 lb/in3 | 4,271.662087 gr/mm3 |
Reverse conversion: Grain per Cubic Millimeter to Pound per Cubic inch
0.4271662087 gr/mm3 × 2.341009143 = 1 lb/in3
0.4271662087 grains per cubic millimeter = 1 pound per cubic inches.
pound per cubic inches = grains per cubic millimeter × 2.34100914286
For a page dedicated to this direction, see Grain per Cubic Millimeter to Pound per Cubic inch.
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 Grain per Cubic Millimeter (gr/mm3)
Mass per volume density.
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.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grains per cubic millimeter are in 1 pound per cubic inch?
1 pound per cubic inch equals 0.4271662087 grains per cubic millimeter, using the exact defined conversion factor rather than an estimate.
How do I convert pound per cubic inch to grain per cubic millimeter?
Multiply the pound per cubic inch value by 0.4271662087. The converter above does this instantly to whatever precision you set.
How do I convert grain per cubic millimeter back to pound per cubic inch?
Use the reverse factor: 1 grain per cubic millimeter equals 2.341009143 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 grain per cubic millimeter?
Grain per Cubic Millimeter (gr/mm3) is a unit of density.
Is the pound per cubic inch to grain per cubic millimeter conversion exact?
Yes. Both pound per cubic inch and grain per cubic millimeter are defined by fixed standards rather than physical artifacts, so the factor of 0.4271662087 used above is exact to as many digits as you choose to display.
Where is the pound per cubic inch still used today?
United States
What's the difference between density and mass concentration?
Density is the mass of a pure substance or material per unit volume. Mass concentration is the mass of one component — like a dissolved solute — within a mixture's total volume. The two use the same kind of units but describe different physical situations.