Carats to Grams Calculator
Convert between carats (ct) and grams (g) instantly. Essential for jewelry, gemstones, diamonds, and precious metals. Enter a value in either unit to get the equivalent weight. Perfect for jewelers, gemologists, and buyers.
What Is a Carat?
A carat (ct) is a unit of mass used primarily for measuring gemstones and pearls. One carat is defined as exactly 200 milligrams (0.2 grams). The carat system originated from the carob seed, which was historically used as a reference for weighing gemstones due to its relatively consistent weight.
The gram (g) is the base unit of mass in the metric system. One gram is defined as one thousandth of a kilogram. The relationship between carats and grams is exact: 1 ct = 0.2 g and 1 g = 5 ct.
How Does the Carats to Grams Calculator Work?
The calculator uses the exact conversion factor:
1 carat = 0.2 grams (exactly)
1 gram = 5 carats (exactly)
To convert carats to grams: g = ct × 0.2
To convert grams to carats: ct = g × 5
The relationship is exact because the carat is defined in terms of the gram.
Simply enter a value in either carats or grams, select the direction of conversion, and the calculator will instantly compute the equivalent weight. The optional pennyweight conversion is also available for jewelers who use this traditional unit.
Why Use This Carats to Grams Calculator?
- Two-Way Conversion: Convert from ct to g and from g to ct.
- Exact Results: Uses the precise conversion factor (0.2).
- Pennyweight Option: Also display weight in pennyweights (dwt) for jewelers.
- Reference Table: Quick reference for common carat values.
- Free & Private: No registration, no data storage.
Common Carat Equivalents
- 1 ct = 0.2 g = 200 mg = 0.1286 dwt
- 5 ct = 1 g = 1000 mg = 0.643 dwt
- 10 ct = 2 g = 0.643 dwt
- 100 ct = 20 g = 12.86 dwt
❓ Carats to Grams Calculator FAQ
What is a carat?
A carat (ct) is a unit of mass used for gemstones and pearls, equal to exactly 200 milligrams (0.2 grams).
How many grams are in a carat?
1 carat = 0.2 grams (exactly).
How many carats are in a gram?
1 gram = 5 carats (exactly).
What is the formula for converting carats to grams?
g = ct × 0.2. For example, 5 ct × 0.2 = 1 g.
What is the formula for converting grams to carats?
ct = g × 5. For example, 2 g × 5 = 10 ct.
What is the difference between a carat and a karat?
A carat (ct) is a unit of mass for gemstones. A karat (K) is a measure of gold purity — 24K is pure gold, 18K is 75% gold. They are completely different units.
How many milligrams are in a carat?
1 carat = 200 milligrams (mg).
What is a pennyweight?
A pennyweight (dwt) is a unit of mass used in jewelry and precious metals. 1 dwt = 1.55517384 grams = 7.77587 carats.
How do I convert carats to pennyweights?
1 carat = 0.1286 dwt. To convert, multiply carats by 0.1286. The calculator can display this conversion when enabled.
What is the carat weight of a 1 gram diamond?
A 1 gram diamond is 5 carats (1 g × 5 = 5 ct).
What is the carat weight of a 0.5 gram gemstone?
A 0.5 gram gemstone is 2.5 carats (0.5 g × 5 = 2.5 ct).
What is the gram weight of a 2 carat diamond?
A 2 carat diamond weighs 0.4 grams (2 ct × 0.2 = 0.4 g).
What is the gram weight of a 0.25 carat gemstone?
A 0.25 carat gemstone weighs 0.05 grams (0.25 ct × 0.2 = 0.05 g).
Why is the carat used for gemstones?
The carat system originated from the carob seed, which was historically used as a reference weight for gemstones due to its relatively consistent mass. It has been standardized at 0.2 grams.
Is this calculator accurate for all gemstones?
Yes. The carat is a unit of mass, independent of the type of gemstone. This calculator converts between carats and grams accurately for any gemstone, diamond, or precious metal.
What is the symbol for carat?
The symbol for carat is ct.
What is the symbol for gram?
The symbol for gram is g.
How do I convert carats to grams in my head?
Multiply the number of carats by 0.2 (or divide by 5). For example, 10 ct × 0.2 = 2 g. For quick estimation, 1 carat is about 0.2 grams.