Carats (ct) to Kilograms (kg) Converter
Enter a value to instantly convert between weight units.
1 Carat = 0.0002 Kilogram
Key Formulas
Kilogram → Pound
lb = kg × 2.20462Pound → Kilogram
kg = lb × 0.453592Gram → Ounce
oz = g × 0.035274Ounce → Gram
g = oz × 28.3495Formula
kg = ct × 0.0000002A carat weighs exactly 200 milligrams (0.2 grams), which means 5 million carats equal 1 kilogram. Gemologists and jewelers use carats because diamonds and other gemstones have been weighed in carats for centuries — the word comes from 'carob,' a seed that was historically used as a weight reference due to its uniformity. Converting carats to kilograms is needed when gemstone weights must be entered into metric-based inventory or grading systems.
Source: NIST SP 811, Table B.8
Frequently Asked Questions
Real-World Examples
A diamond wholesaler pricing a million-carat parcel needs to know it's exactly 1 kg for insurance documentation.
5000000 ct = 1 kg
A jewelry manufacturer receiving 1,000,000 carats of melee diamonds (small stones) gets 0.2 kg of material.
1000000 ct = 0.2 kg
A gemstone grading report shows 25,000 carats of material — 0.005 kg for the certificate.
25000 ct = 0.005 kg
A single 1-carat diamond (500 points) weighs 0.0001 kg — 100 mg on a precision scale.
500 ct = 0.0001 kg