Grain to Carat Converter
Weight · unit-converter
Convert Grain to Carat with a fixed input and output unit, step-by-step formula line, and reference tables. All calculations use gram-based factors (international avoirdupois pound and metric definitions). The full Weight Converter also includes carat, grain, and US/UK hundredweight.
Calculator
From: Grain (gr)
To: Carat (ct)
About Grain
The grain is 1/7000 of a pound (exactly 64.79891 mg). It is used in ballistics, pharmacy, and precious-metal contexts.
About Carat
The metric carat is exactly 0.2 grams (200 mg), commonly used for gemstones and jewelry.
How to convert grains to carats
1 grain is equal to 0.32399455 carat:
1 gr = (0.06479891 g ÷ 0.2 g) ct = 0.32399455 ct
Each grain is defined as 0.06479891 g and each carat as 0.2 g, so one gr equals 0.06479891 ÷ 0.2 ct = 0.32399455 ct.
Let w(gr) be the numeric value of the same mass measured in Grain (gr), and w(ct) the value in Carat (ct). Then:
w(ct) = w(gr) × (0.06479891 / 0.2)
Equivalently, divide by how many gr fit into one ct (grams per ct divided by grams per gr):
w(ct) = w(gr) ÷ 3.08647167058829
Or: carat = grain ÷ 3.08647167058829
Examples
Example #1: Convert 20 gr to carat
20 gr = 20 gr × (0.06479891/0.2) ct = 6.479891 ct
20 gr = 20 gr ÷ 3.08647167058829 = 6.479891 ct
Example #2: Convert 50 gr to carat
50 gr = 50 gr × (0.06479891/0.2) ct = 16.1997275 ct
50 gr = 50 gr ÷ 3.08647167058829 = 16.1997275 ct
Summary
To convert Grain to Carat, multiply the value in gr by the ratio of grams per gr divided by grams per ct. Equivalently: value_ct = value_gr × (0.06479891 / 0.2). Numerically, 1 gr equals 0.32399455 ct.
Relationship context
You are converting between imperial / UK (stone, long ton, pound, ounce) (Grains) and metric (SI) (Carats). Metric mass is decimal from the gram; US and imperial masses use pounds and ounces with fixed definitions relative to the kilogram. The numeric factor used here is 3.239945e-1.
Conversion tables
| Grain (gr) | Carat (ct) |
|---|---|
| 0.1 | 0.032399455 |
| 1 | 0.32399455 |
| 2 | 0.6479891 |
| 3 | 0.97198365 |
| 4 | 1.2959782 |
| 5 | 1.61997275 |
| 6 | 1.9439673 |
| 7 | 2.26796185 |
| 8 | 2.5919564 |
| 9 | 2.91595095 |
| Grain (gr) | Carat (ct) |
|---|---|
| 10 | 3.2399455 |
| 20 | 6.479891 |
| 30 | 9.7198365 |
| 40 | 12.959782 |
| 50 | 16.1997275 |
| 60 | 19.439673 |
| 70 | 22.6796185 |
| 80 | 25.919564 |
| 90 | 29.1595095 |
| 100 | 32.399455 |