Convert Carats to Grains
1 carat (ct) equals 3.086471671 grains (gr).
1 ct = 3.086471671 gr
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk carat to grain converter to paste a column from Excel.
How to Convert Carat to Grain
- 1 ct = 3.086471671 gr
- 1 gr = 0.32399455 ct
- Example: convert 15 ct to gr: 15 ct = 15 × 3.086471671 gr = 46.29707506 gr
Reference conditions. gr: Avoirdupois system: 1 lb = 16 oz = 7000 grains = 0.45359237 kg exactly (1959 agreement).
Formula
gr = ct × 3.086471670588
Derivation from SI units:
- 1 ct = 200 mg (metric carat, exact)
- 1 gr = 1/7000 lb = 64.79891 mg (exact)
- 1 ct = 0.0002 kg ÷ 0.00006479891 kg per gr = 3.086471670588 gr
Both units are defined exactly, so the factor is exact. Carat definition: carat; Grain definition: grain.
Worked examples
- A reading of 0.75 ct converts to 2.314853753 gr.
0.75 ct × 3.086471671 = 2.314853753 gr - A value of 3 ct is 9.259415012 gr.
3 ct × 3.086471671 = 9.259415012 gr
Carat to Grain conversion table
| Carats (ct) | Grains (gr) |
|---|---|
| 0.1 ct | 0.3086471671 gr |
| 0.25 ct | 0.7716179176 gr |
| 0.5 ct | 1.543235835 gr |
| 0.75 ct | 2.314853753 gr |
| 1 ct | 3.086471671 gr |
| 1.5 ct | 4.629707506 gr |
| 2 ct | 6.172943341 gr |
| 3 ct | 9.259415012 gr |
| 5 ct | 15.43235835 gr |
| 10 ct | 30.86471671 gr |
| 100 ct | 308.6471671 gr |
Where it's used
Carats are used for diamonds and gemstones, while grains appear in bullet and powder weights. Both measure mass (commonly called weight), so the conversion is a fixed factor.
Carat to other weight and mass units
| Conversion | 1 ct equals |
|---|---|
| carat to kilogram | 0.0002 kg |
| carat to gram | 0.2 g |
| carat to milligram | 200 mg |
| carat to microgram | 200000 µg |
| carat to metric ton | 2 × 10⁻⁷ t |
| carat to pound | 0.0004409245244 lb |
| carat to ounce | 0.00705479239 oz |
| carat to stone | 0.00003149460888 st |
| carat to short ton | 2.204622622 × 10⁻⁷ ton (US) |
| carat to long ton | 1.968413055 × 10⁻⁷ ton (UK) |
| carat to grain | 3.086471671 gr |
| carat to troy ounce | 0.006430149314 oz t |
Frequently asked questions
How many grains are in 1 carat?
1 ct = 3.086471671 gr.
How do I convert carats to grains?
Multiply the value in ct by 3.086471671. For example, 15 ct × 3.086471671 = 46.29707506 gr.
Is the ct to gr conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "carat, metric".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "grain (gr)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Carats to Grains. Retrieved October 17, 2026, from https://scientificconverters.com/mass/carats-to-grains/
IEEE
Scientific Converters, "Convert Carats to Grains," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/mass/carats-to-grains/