Mass per volume density.
Stones per Cup to Grains per Cubic Millimeter Converter — st/cup to gr/mm3
Convert Stone per Cup (st/cup) to Grain per Cubic Millimeter (gr/mm3) using the exact conversion factor (1 stone per cup = 0.4142217781 grain per cubic millimeter). See the formula, worked examples, and conversion table.
Stones per Cup 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 26841.11972 / 64798.91.
Density uses kilograms per cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Stones per Cup to Grains per Cubic Millimeter
Stone per Cup 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. Both are mass per volume density units.
Formula
grains per cubic millimeter = stones per cup × 0.414221778098
This factor comes from each unit's defined relationship to the category's base unit: 1 stone per cup equals 26841.119719 base units, and 1 grain per cubic millimeter equals 64798.91 base units, so dividing one by the other gives the direct stone per cup-to-grain per cubic millimeter factor of 0.414221778098.
Simple example
1 st/cup × 0.4142217781 = 0.4142217781 gr/mm3
1 stone per cup = 0.4142217781 grains per cubic millimeter.
Real-world example
1,000 st/cup × 0.4142217781 = 414.2217781 gr/mm3
1,000 stones per cup = 414.2217781 grains per cubic millimeter.
Conversion table
| Stone per Cup (st/cup) | Grain per Cubic Millimeter (gr/mm3) |
|---|---|
| 0.1 st/cup | 0.0414221778 gr/mm3 |
| 1 st/cup | 0.4142217781 gr/mm3 |
| 10 st/cup | 4.142217781 gr/mm3 |
| 100 st/cup | 41.42217781 gr/mm3 |
| 1,000 st/cup | 414.2217781 gr/mm3 |
| 10,000 st/cup | 4,142.217781 gr/mm3 |
Reverse conversion: Grain per Cubic Millimeter to Stone per Cup
0.4142217781 gr/mm3 × 2.414165679 = 1 st/cup
0.4142217781 grains per cubic millimeter = 1 stones per cup.
stones per cup = grains per cubic millimeter × 2.41416567857
For a page dedicated to this direction, see Grain per Cubic Millimeter to Stone per Cup.
Understanding the Stone per Cup (st/cup)
Mass per volume density.
Understanding the Grain per Cubic Millimeter (gr/mm3)
Mass per volume density.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grains per cubic millimeter are in 1 stone per cup?
1 stone per cup equals 0.4142217781 grains per cubic millimeter, using the exact defined conversion factor rather than an estimate.
How do I convert stone per cup to grain per cubic millimeter?
Multiply the stone per cup value by 0.4142217781. The converter above does this instantly to whatever precision you set.
How do I convert grain per cubic millimeter back to stone per cup?
Use the reverse factor: 1 grain per cubic millimeter equals 2.414165679 stones per cup. You can also use the swap control in the converter above to flip the direction instantly.
What is a stone per cup?
Stone per Cup (st/cup) is a unit of density.
What is a grain per cubic millimeter?
Grain per Cubic Millimeter (gr/mm3) is a unit of density.
Is the stone per cup to grain per cubic millimeter conversion exact?
Yes. Both stone per cup and grain per cubic millimeter are defined by fixed standards rather than physical artifacts, so the factor of 0.4142217781 used above is exact to as many digits as you choose to display.
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.