Grain to Carat Converter
Convert Grain (gr) to Carat (ct) instantly. 1 gr = 0.323995 ct.
Mass Converter
26 units available
1 gr = 0.323995 ct
Formula:
ct = gr × 0.32399455With your value: 1 gr = 0.32399455 ct
How big is that?
Everyday references on a logarithmic scale, all expressed in grain so you can sanity-check the result.
Other Grain to Carat conversions
Grain to Carat Conversion Table
| Grain (gr) | Carat (ct) |
|---|---|
| 0.5 | 0.161997 |
| 1 | 0.323995 |
| 2 | 0.647989 |
| 5 | 1.619973 |
| 10 | 3.239945 |
| 15 | 4.859918 |
| 20 | 6.479891 |
| 25 | 8.099864 |
| 50 | 16.199727 |
| 100 | 32.399455 |
| 250 | 80.998638 |
| 500 | 161.997275 |
| 1000 | 323.99455 |
Carat to Grain Conversion Table
| Carat (ct) | Grain (gr) |
|---|---|
| 0.5 | 1.543236 |
| 1 | 3.086472 |
| 2 | 6.172943 |
| 5 | 15.432358 |
| 10 | 30.864717 |
| 15 | 46.297075 |
| 20 | 61.729433 |
| 25 | 77.161792 |
| 50 | 154.323584 |
| 100 | 308.647167 |
| 250 | 771.617918 |
| 500 | 1,543.235835 |
| 1000 | 3,086.471671 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Grain (gr)
Mass
Traceable to the kilogram, defined by fixing the Planck constant at 6.626 070 15 × 10⁻³⁴ J·s. Avoirdupois masses derive from the 1959 international pound (0.453 592 37 kg exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
Carat (ct)
Mass
The metric carat is exactly 200 mg, agreed internationally in 1907.
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
How to Convert Grain to Carat
To convert from Grain (gr) to Carat (ct), multiply the value by 0.32399455.
Formula: ct = gr × 0.32399455
Reverse: gr = ct × 3.0864716706
Step-by-Step Example
- Start with your value in Grain. For example: 5 gr
- Multiply by the conversion factor: 5 x 0.32399455
- The result is: 1.619973 ct
About Grain
The grain equals exactly 64.79891 milligrams and was originally the weight of a single barleycorn. It is still the standard unit for bullets, propellant and arrows.
Common uses: ammunition, archery, pharmacy (historic).
About Carat
The carat equals 200 milligrams and is the standard unit for measuring gemstone weight.
Fun Fact: The word "carat" comes from the carob seed, which was used as a balance weight in ancient gem trading.
Common uses: gemstones, diamonds, jewelry.
Frequently Asked Questions
How many Carat are in 1 Grain?
There are exactly 0.32399455 Carat in 1 Grain. This means the conversion factor from Grain to Carat is 0.32399455.
What is the formula to convert Grain to Carat?
The formula to convert Grain to Carat is: ct = gr × 0.32399455. For example, to convert 10 Grain to Carat, you would multiply 10 by 0.32399455.
What is a Grain?
The grain equals exactly 64.79891 milligrams and was originally the weight of a single barleycorn. It is still the standard unit for bullets, propellant and arrows.
What is a Carat?
The carat equals 200 milligrams and is the standard unit for measuring gemstone weight.
What are the common uses of Grain?
The Grain is commonly used in ammunition, archery, pharmacy (historic).
Related Mass Conversions
Cite this page
UnitConvertLab. (2026). Grain to Carat converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/grain-to-carat