Mass per volume density.
Carats per Cup to Stone per Cubic inches Converter — ct/cup to st/in3
Convert Carat per Cup (ct/cup) to Stone per Cubic inch (st/in3) using the exact conversion factor (1 carat per cup = 0.0000021814 stone per cubic inch). See the formula, worked examples, and conversion table.
Carats per Cup to Stone 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 0.8453505675 / 387518.6659.
Density uses kilograms per cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Carats per Cup to Stone per Cubic inches
Carat per Cup and Stone 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. Both are mass per volume density units.
Formula
stone per cubic inches = carats per cup × 0.00000218144477116
This factor comes from each unit's defined relationship to the category's base unit: 1 carat per cup equals 0.845350567546 base units, and 1 stone per cubic inch equals 387518.665943 base units, so dividing one by the other gives the direct carat per cup-to-stone per cubic inch factor of 0.00000218144477116.
Simple example
1 ct/cup × 0.000002181444771 = 0.0000021814 st/in3
1 carat per cup = 0.0000021814 stone per cubic inches.
Real-world example
1,000 ct/cup × 0.000002181444771 = 0.0021814448 st/in3
1,000 carats per cup = 0.0021814448 stone per cubic inches.
Conversion table
| Carat per Cup (ct/cup) | Stone per Cubic inch (st/in3) |
|---|---|
| 0.1 ct/cup | 2.181445e-7 st/in3 |
| 1 ct/cup | 0.0000021814 st/in3 |
| 10 ct/cup | 0.0000218144 st/in3 |
| 100 ct/cup | 0.0002181445 st/in3 |
| 1,000 ct/cup | 0.0021814448 st/in3 |
| 10,000 ct/cup | 0.0218144477 st/in3 |
Reverse conversion: Stone per Cubic inch to Carat per Cup
0.0000021814 st/in3 × 458411.7889 = 0.9999794764 ct/cup
0.0000021814 stone per cubic inches = 0.9999794764 carats per cup.
carats per cup = stone per cubic inches × 458411.788931
For a page dedicated to this direction, see Stone per Cubic inch to Carat per Cup.
Understanding the Carat per Cup (ct/cup)
Mass per volume density.
Understanding the Stone per Cubic inch (st/in3)
Mass per volume density.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many stone per cubic inches are in 1 carat per cup?
1 carat per cup equals 0.0000021814 stone per cubic inches, using the exact defined conversion factor rather than an estimate.
How do I convert carat per cup to stone per cubic inch?
Multiply the carat per cup value by 0.000002181444771. The converter above does this instantly to whatever precision you set.
How do I convert stone per cubic inch back to carat per cup?
Use the reverse factor: 1 stone per cubic inch equals 458,411.7889 carats per cup. You can also use the swap control in the converter above to flip the direction instantly.
What is a carat per cup?
Carat per Cup (ct/cup) is a unit of density.
What is a stone per cubic inch?
Stone per Cubic inch (st/in3) is a unit of density.
Is the carat per cup to stone per cubic inch conversion exact?
Yes. Both carat per cup and stone per cubic inch are defined by fixed standards rather than physical artifacts, so the factor of 0.000002181444771 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.