Convert Carat (metric) to Gram
Convert carats (metric) to grams instantly. 1 carat (metric) = 0.2 gram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Gram to Carat (metric) converter for the reverse conversion.
Units explained
Carat (metric)
The metric carat (ct) equals exactly 200 milligrams (0.0002 kg).
From Arabic 'qirat' and Greek 'keration', the carob seed once used as a counterweight.
The worldwide standard for gemstone and diamond mass.
The metric carat was fixed at 200 mg internationally in 1907.
Gram
The gram (g) equals one-thousandth of a kilogram.
From Late Latin 'gramma', a small weight or scruple.
The everyday metric unit for food, medicine, and small objects.
Defined in 1795 as the mass of one cubic centimeter of water at melting point.
Carat (metric) to Gram conversion formula
The relationship between carats (metric) and grams:
To convert carats (metric) to grams, multiply the value in carats (metric) by 0.2. To reverse, multiply grams by 5.
How to use this converter
Type a value into the calculator. The result in grams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Gram to Carat (metric) converter for the reverse direction.
Step-by-step: convert carats (metric) to grams
- Write down the value in carats (metric) (ct).
- Multiply that value by the factor 0.2.
- The product is the equivalent value in grams (g).
- To reverse, multiply the gram value by 5.
Worked examples
Example 1 — Convert 1 ct to g:
1 × 0.2 = 0.2 g
Example 2 — Convert 100 ct to g:
100 × 0.2 = 20 g
Real-world example — Packaging gauge
A 4-carat (metric) plastic bag thickness is a common spec for grocery and freezer bags. Converting from carats (metric) to grams is what packaging buyers do whenever they bridge US and metric supplier quotes.
4 ct × 0.2 = 0.8 g
Real-world example — Plastic film and laminate thickness
A 500-carat (metric) sheet is a typical spec for ID-card laminates and film overlays. Converting to grams aligns the value with the unit most CAD systems and material datasheets prefer.
500 ct × 0.2 = 100 g
Carat (metric) to Gram conversion table
Standard reference values for converting carats (metric) to grams:
| Carat (metric) [ct] | Gram [g] |
|---|---|
| 0.01 | 0.002 |
| 0.1 | 0.02 |
| 1 | 0.2 |
| 2 | 0.4 |
| 3 | 0.6 |
| 4 | 0.8 |
| 5 | 1 |
| 10 | 2 |
| 20 | 4 |
| 30 | 6 |
| 40 | 8 |
| 50 | 10 |
| 100 | 20 |
| 500 | 100 |
| 1000 | 200 |
Frequently asked questions
How many grams is 1 carat (metric)?
How do I convert carats (metric) to grams?
How do I convert grams back to carats (metric)?
How many grams is 100 carats (metric)?
Popular weight unit conversions
Convert Carat (metric) to other weight units
Show all Carat (metric) conversions
Metric / SI (18 units)
Avoirdupois (15 units)
Troy & Apothecary (9 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 ct = 0.2 g) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.