Mass per volume density.
Grains per Cup to Grains per Fluid ounce Converter — gr/cup to gr/fl oz
Convert Grain per Cup (gr/cup) to Grain per Fluid ounce (gr/fl oz) using the exact conversion factor (1 grain per cup = 0.125 grain per fluid ounce). See the formula, worked examples, and conversion table.
Grains per Cup to Grains per Fluid ounce 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 0.2738889767 / 2.191111814.
Density uses kilograms per cubic meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Grains per Cup to Grains per Fluid ounce
Grain per Cup and Grain per Fluid ounce 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 fluid ounce = grains per cup × 0.125
This factor comes from each unit's defined relationship to the category's base unit: 1 grain per cup equals 0.273888976724 base units, and 1 grain per fluid ounce equals 2.19111181379 base units, so dividing one by the other gives the direct grain per cup-to-grain per fluid ounce factor of 0.125.
Simple example
1 gr/cup × 0.125 = 0.125 gr/fl oz
1 grain per cup = 0.125 grains per fluid ounce.
Real-world example
1,000 gr/cup × 0.125 = 125 gr/fl oz
1,000 grains per cup = 125 grains per fluid ounce.
Conversion table
| Grain per Cup (gr/cup) | Grain per Fluid ounce (gr/fl oz) |
|---|---|
| 0.1 gr/cup | 0.0125 gr/fl oz |
| 1 gr/cup | 0.125 gr/fl oz |
| 10 gr/cup | 1.25 gr/fl oz |
| 100 gr/cup | 12.5 gr/fl oz |
| 1,000 gr/cup | 125 gr/fl oz |
| 10,000 gr/cup | 1,250 gr/fl oz |
Reverse conversion: Grain per Fluid ounce to Grain per Cup
0.125 gr/fl oz × 8 = 1 gr/cup
0.125 grains per fluid ounce = 1 grain per cup.
grains per cup = grains per fluid ounce × 8
For a page dedicated to this direction, see Grain per Fluid ounce to Grain per Cup.
Understanding the Grain per Cup (gr/cup)
Mass per volume density.
Understanding the Grain per Fluid ounce (gr/fl oz)
Mass per volume density.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many grains per fluid ounce are in 1 grain per cup?
1 grain per cup equals 0.125 grains per fluid ounce, using the exact defined conversion factor rather than an estimate.
How do I convert grain per cup to grain per fluid ounce?
Multiply the grain per cup value by 0.125. The converter above does this instantly to whatever precision you set.
How do I convert grain per fluid ounce back to grain per cup?
Use the reverse factor: 1 grain per fluid ounce equals 8 grains per cup. You can also use the swap control in the converter above to flip the direction instantly.
What is a grain per cup?
Grain per Cup (gr/cup) is a unit of density.
What is a grain per fluid ounce?
Grain per Fluid ounce (gr/fl oz) is a unit of density.
Is the grain per cup to grain per fluid ounce conversion exact?
Yes. Both grain per cup and grain per fluid ounce are defined by fixed standards rather than physical artifacts, so the factor of 0.125 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.