Mass and Weight · Unit Converter

Convert Carat (metric) to Electron Mass (rest)

Convert carats (metric) to electron mass (rest) instantly. 1 carat (metric) = 2.195537e+26 electron mass (rest) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Electron Mass (rest) 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.

Scientific / Atomic

Electron Mass (rest)

What is a electron mass (rest)?

The electron rest mass is about 9.109E-31 kg.

Origin of the electron mass (rest)

The mass of the electron, the lightest charged elementary particle.

Where it is used

Atomic and particle physics.

When and where it was developed

Quantified after J. J. Thomson identified the electron in 1897.

Carat (metric) to Electron Mass (rest) conversion formula

Note: this conversion uses a generally accepted modern value. Historical and regional definitions of this unit varied across times and places.

The relationship between carats (metric) and electron mass (rest):

1 ct = 2.195537e+26 me

1 me = 4.554695e-27 ct

To convert carats (metric) to electron mass (rest), multiply the value in carats (metric) by 2.195537e+26. To reverse, multiply electron mass (rest) by 4.554695e-27.

How to use this converter

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

Step-by-step: convert carats (metric) to electron mass (rest)

Write down the value in carats (metric) (ct).
Multiply that value by the factor 2.195537e+26.
The product is the equivalent value in electron mass (rest) (me).
To reverse, multiply the electron mass (rest) value by 4.554695e-27.

Worked examples

Example 1 — Convert 1 ct to me:
1 × 2.195537e+26 = 2.195537e+26 me

Example 2 — Convert 100 ct to me:
100 × 2.195537e+26 = 2.195537e+28 me

Real-world example — Mid-micron to nanometer

3 carats (metric) equals 3,000 electron mass (rest) — useful when relating mid-infrared wavelengths (typically quoted in microns) to nanometer-scale visible-light wavelength tables.

3 ct × 2.195537e+26 = 6.58661e+26 me

Real-world example — From microns to sub-micron features

One carat (metric) equals one thousand electron mass (rest) — the conversion semiconductor designers do constantly when comparing mask feature dimensions to actual transistor gate lengths.

1 ct × 2.195537e+26 = 2.195537e+26 me

Real-world example — Infrared to visible-spectrum mapping

A 10-carat (metric) thermal infrared wavelength corresponds to a much larger number in electron mass (rest), the unit favoured for ultraviolet and visible-light specifications.

10 ct × 2.195537e+26 = 2.195537e+27 me

Carat (metric) to Electron Mass (rest) conversion table

Standard reference values for converting carats (metric) to electron mass (rest):

Carat (metric) [ct]	Electron Mass (rest) [me]
0.01	2.195537e+24
0.1	2.195537e+25
1	2.195537e+26
2	4.391074e+26
3	6.58661e+26
4	8.782147e+26
5	1.097768e+27
10	2.195537e+27
20	4.391074e+27
30	6.58661e+27
40	8.782147e+27
50	1.097768e+28
100	2.195537e+28
500	1.097768e+29
1000	2.195537e+29

Frequently asked questions

How many electron mass (rest) is 1 carat (metric)?

1 carat (metric) equals 2.195537e+26 electron mass (rest).

How do I convert carats (metric) to electron mass (rest)?

Multiply the value in carats (metric) by 2.195537e+26 to get electron mass (rest).

How do I convert electron mass (rest) back to carats (metric)?

Multiply the value in electron mass (rest) by 4.554695e-27, or use the Electron Mass (rest) to Carat (metric) converter.

How many electron mass (rest) is 100 carats (metric)?

100 carats (metric) equals 2.195537e+28 electron mass (rest), because 100 × 2.195537e+26 = 2.195537e+28.

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 = 2.195537e+26 me) 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.