Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Unit Converters
Carats to Grams Converter
grams = carats × 0.2. 5 ct = 1 g.
A metric carat is 0.2 g, defined in 1907 so jewelers would stop arguing. A 1 ct diamond is 0.2 g — the size you see is cut, not this mass. Gold “karat” (purity) is a different word on purpose.
Carats
ct → g
0.2 g
A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
- You typed
- 1 ct
- One g is
- 5 ct
- How it’s calculated
- grams = carats × 0.2. 5 ct = 1 g.
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Carats
The “Carats” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
A metric carat is 0.2 g, defined in 1907 so jewelers would stop arguing. A 1 ct diamond is 0.2 g — the size you see is cut, not this mass. Gold “karat” (purity) is a different word on purpose. grams = carats × 0.2. 5 ct = 1 g. Example: A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
grams = carats × 0.2. 5 ct = 1 g.
Example: A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
When to use this Carats to Grams
Common use cases
- A metric carat is 0.2 g, defined in 1907 so jewelers would stop arguing. A 1 ct diamond is 0.2 g — the size you see is cut, not this mass. Gold “karat” (purity) is a different word on purpose.
- Sanity-check with this case: A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
- The relationship is: grams = carats × 0.2. 5 ct = 1 g.
Localized examples
- Unit Converters: the example on this page uses the same formula as the widget.
What you get
- Fields: Carats
- grams = carats × 0.2. 5 ct = 1 g.
- Example on the page: A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
How to Convert Carats to Grams Step-by-Step
- 1Enter Carats. Use the values you have, not a catalog average, unless that is all you know.
- 2grams = carats × 0.2. 5 ct = 1 g.
- 3Worked case: A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
- 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.
Governing formula
grams = carats × 0.2. 5 ct = 1 g.
A 2.5 ct stone is 0.5 g. 100 ct of gem rough is 20 g.
Example: set Carats = 1, then read the result.
Variable definitions
- value
Carats
The “Carats” field. Default 1; typical range 0–10000.
- The conversion (grams = carats × 0.2. 5 ct = 1 g.) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Carat is mass. Karat is gold purity (24K = pure). Do not convert 18K with this page.
Related calculators
Unit Converters
- Carats to MilligramsThe metric carat is exactly 200 mg (0.2 g) since 1907. A 1 ct diamond is 200 mg. Jewelers still cut “points” (0.01 ct = 2 mg). This is not a gold-karat purity scale.
- SI Gram Prefix ConverterMass prefixes attach to the gram, not the kilogram. Kilogram is already kilo + gram. Scale yottagram down to yoctogram, or milligram to microgram, without mixing in pounds. Jewelry carats and troy ounces are separate legal pages.
- Atomic Mass Units to GramsDaltons (u) are how chemists weigh atoms. Carbon-12 is defined as 12 u. The gram is 6.022 × 10²³ of those, which is why a mole of carbon is 12 g. This page is for lab sheets, not grocery bags.
- Brown Sugar Cups to GramsPacked light or dark brown sugar is about 220 g per US cup. “Packed” means you pressed it. A loose scoop can miss 30 g and flatten cookies. Light and dark weigh nearly the same; molasses is the flavor, not the scale.
- Butter Sticks to GramsA US stick is ½ cup, 8 tablespoons, 4 oz, 113 g. European blocks are often 250 g. If a UK recipe says “8 oz butter,” that is two US sticks, not a European brick.
- Cocoa Powder Cups to GramsUnsweetened cocoa powder is fluffy. A US cup is about 85 g sifted/spooned. Dutch-process vs natural does not change the gram target as much as how hard you tap the cup.
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See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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