Mass and Weight · Unit Converter

Convert Carat (metric) to Kilogram

Convert carats (metric) to kilograms instantly. 1 carat (metric) = 0.0002 kilogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Kilogram to Carat (metric) converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Dr. Ashok Kumar K, Ph.D.

Mass and Weight category 2 min read Published June 10, 2026 Last reviewed June 10, 2026 Updated June 10, 2026

Units explained

Troy & Apothecary

Carat (metric)

What is a carat (metric)?

The metric carat (ct) equals exactly 200 milligrams (0.0002 kg).

Origin of the carat (metric)

From Arabic 'qirat' and Greek 'keration', the carob seed once used as a counterweight.

Where it is used

The worldwide standard for gemstone and diamond mass.

When and where it was developed

The metric carat was fixed at 200 mg internationally in 1907.

Metric / SI

Kilogram

What is a kilogram?

The kilogram (kg) is the SI base unit of mass, defined by fixing the Planck constant h at 6.62607015E-34 J s.

Origin of the kilogram

From Greek 'khilioi' (thousand) plus 'gramma' (small weight).

Where it is used

The worldwide base unit of mass in science, commerce, and everyday life.

When and where it was developed

Adopted in 1795; redefined through the Planck constant on 20 May 2019.

Carat (metric) to Kilogram conversion formula

The relationship between carats (metric) and kilograms:

1 ct = 0.0002 kg

1 kg = 5000 ct

To convert carats (metric) to kilograms, multiply the value in carats (metric) by 0.0002. To reverse, multiply kilograms by 5000.

How to use this converter

Type a value into the calculator. The result in kilograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kilogram to Carat (metric) converter for the reverse direction.

Step-by-step: convert carats (metric) to kilograms

Write down the value in carats (metric) (ct).
Multiply that value by the factor 0.0002.
The product is the equivalent value in kilograms (kg).
To reverse, multiply the kilogram value by 5000.

Worked examples

Example 1 — Convert 1 ct to kg:
1 × 0.0002 = 0.0002 kg

Example 2 — Convert 100 ct to kg:
100 × 0.0002 = 0.02 kg

Real-world example — Macro-scale buildup

A million carats (metric) equals exactly one kilogram — the conversion that bridges microscale features and macroscale objects in microfluidic, biomedical, and semiconductor packaging design.

1000000 ct × 0.0002 = 200 kg

Real-world example — Quarter-meter measurement reference

A 250,000-carat (metric) length equals 0.25 kilograms — useful for comparing supply-chain spec sheets where some lengths are quoted in the smaller unit and some in the larger.

250000 ct × 0.0002 = 50 kg

Real-world example — From microscopic to macroscopic

A million carats (metric) equals exactly one kilogram. This kind of conversion appears in microfluidics, where total channel length is given in kilograms but feature widths are in carats (metric).

1000000 ct × 0.0002 = 200 kg

Carat (metric) to Kilogram conversion table

Standard reference values for converting carats (metric) to kilograms:

Carat (metric) [ct]	Kilogram [kg]
0.01	2e-6
0.1	2e-5
1	0.0002
2	0.0004
3	0.0006
4	0.0008
5	0.001
10	0.002
20	0.004
30	0.006
40	0.008
50	0.01
100	0.02
500	0.1
1000	0.2

Frequently asked questions

How many kilograms is 1 carat (metric)?

1 carat (metric) equals 0.0002 kilogram.

How do I convert carats (metric) to kilograms?

Multiply the value in carats (metric) by 0.0002 to get kilograms.

How do I convert kilograms back to carats (metric)?

Multiply the value in kilograms by 5000, or use the Kilogram to Carat (metric) converter.

How many kilograms is 100 carats (metric)?

100 carats (metric) equals 0.02 kilograms, because 100 × 0.0002 = 0.02.

Convert Carat (metric) to other weight units

Show all Carat (metric) conversions

Metric / SI (18 units)

Avoirdupois (15 units)

Troy & Apothecary (9 units)

Carat (metric) to Point (1/100 carat) (pt) Carat (metric) to Scruple (apothecary) (s ap) Carat (metric) to Pennyweight (dwt) Carat (metric) to Momme (mom) Carat (metric) to Mace (mace) Carat (metric) to Dram (apothecary/troy) (dr ap) Carat (metric) to Troy Ounce (oz t) Carat (metric) to Tael (tael) Carat (metric) to Pound (troy/apothecary) (lb t)

Indian / South Asian (6 units)

Carat (metric) to Ratti (ratti) Carat (metric) to Masha (masha) Carat (metric) to Tola (tola) Carat (metric) to Chittack (Chatank) (chittack) Carat (metric) to Seer (Ser) (seer) Carat (metric) to Maund (Mann) (maund)

Scientific / Atomic (9 units)

Carat (metric) to Electron Mass (rest) (me) Carat (metric) to MeV/c2 (MeV/c²) Carat (metric) to Muon Mass (mµ) Carat (metric) to Atomic Mass Unit (u) Carat (metric) to Proton Mass (mp) Carat (metric) to Neutron Mass (mn) Carat (metric) to Deuteron Mass (md) Carat (metric) to Carbon-12 Atom Mass (C-12) Carat (metric) to Planck Mass (mP)

Astronomical (4 units)

Carat (metric) to Lunar Mass (Moon) (M☾) Carat (metric) to Earth's Mass (M⊕) Carat (metric) to Jupiter Mass (MJ) Carat (metric) to Sun's Mass (M☉)

Biblical / Ancient (14 units)

Carat (metric) to Lepton (Biblical Roman) (lepton) Carat (metric) to Quadrans (Biblical Roman) (quadrans) Carat (metric) to Assarion (Biblical Roman) (assarion) Carat (metric) to Gerah (Biblical Hebrew) (gerah) Carat (metric) to Drachma (Biblical Greek) (drachma) Carat (metric) to Denarius (Biblical Roman) (denarius) Carat (metric) to Bekan (Biblical Hebrew) (bekah) Carat (metric) to Didrachma (Biblical Greek) (didrachma) Carat (metric) to Shekel (Biblical Hebrew) (shekel) Carat (metric) to Tetradrachma (Biblical Greek) (tetra) Carat (metric) to Mina (Biblical Greek) (mina) Carat (metric) to Mina (Biblical Hebrew) (mina) Carat (metric) to Talent (Biblical Greek) (talent) Carat (metric) to Talent (Biblical Hebrew) (talent)

Force / Engineering (5 units)

Carat (metric) to Poundal (pdl) Carat (metric) to Ton (assay) (US) (AT) Carat (metric) to Ton (assay) (UK) (AT) Carat (metric) to Kilogram-force square second/meter (hyl) Carat (metric) to Slug (slug)

Sources & references

Conversion factor (1 ct = 0.0002 kg) 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.

Results are provided for general reference. Verify critical measurements against an authoritative standard.