Mass and Weight · Unit Converter

Convert Gram to Atomic Mass Unit

Convert grams to atomic mass unit instantly. 1 gram = 6.022137e+23 atomic mass unit — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Atomic Mass Unit to Gram 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 Last reviewed Updated

Units explained

Metric / SI

Gram

What is a gram?

The gram (g) equals one-thousandth of a kilogram.

Origin of the gram

From Late Latin 'gramma', a small weight or scruple.

Where it is used

The everyday metric unit for food, medicine, and small objects.

When and where it was developed

Defined in 1795 as the mass of one cubic centimeter of water at melting point.

Scientific / Atomic

Atomic Mass Unit

What is a atomic mass unit?

One unified atomic mass unit (u) is defined as 1/12 the mass of a carbon-12 atom, about 1.6605E-27 kg.

Origin of the atomic mass unit

Introduced to give atomic and molecular masses convenient numerical values.

Where it is used

Atomic, molecular, and nuclear physics and chemistry.

When and where it was developed

The unified (carbon-12) scale was adopted by IUPAC and IUPAP in 1960-1961.

Gram to Atomic Mass Unit conversion formula

The relationship between grams and atomic mass unit:

1 g = 6.022137e+23 u
1 u = 1.66054e-24 g

To convert grams to atomic mass unit, multiply the value in grams by 6.022137e+23. To reverse, multiply atomic mass unit by 1.66054e-24.

How to use this converter

Type a value into the calculator. The result in atomic mass unit updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Atomic Mass Unit to Gram converter for the reverse direction.

Step-by-step: convert grams to atomic mass unit

  1. Write down the value in grams (g).
  2. Multiply that value by the factor 6.022137e+23.
  3. The product is the equivalent value in atomic mass unit (u).
  4. To reverse, multiply the atomic mass unit value by 1.66054e-24.

Worked examples

Example 1 — Convert 1 g to u:
1 × 6.022137e+23 = 6.022137e+23 u

Example 2 — Convert 100 g to u:
100 × 6.022137e+23 = 6.022137e+25 u

Real-world example — Centimeter to wavelength scale

One gram equals 10 million atomic mass unit. Physics curricula use this kind of conversion to relate everyday measurements to atomic and optical scales.

1 g × 6.022137e+23 = 6.022137e+23 u

Real-world example — Small-scale to atomic-scale

One gram equals 10 million atomic mass unit — useful for physics curricula that relate everyday measurements to atomic and optical scales.

1 g × 6.022137e+23 = 6.022137e+23 u

Gram to Atomic Mass Unit conversion table

Standard reference values for converting grams to atomic mass unit:

Gram [g]Atomic Mass Unit [u]
0.016.022137e+21
0.16.022137e+22
16.022137e+23
21.204427e+24
31.806641e+24
42.408855e+24
53.011068e+24
106.022137e+24
201.204427e+25
301.806641e+25
402.408855e+25
503.011068e+25
1006.022137e+25
5003.011068e+26
10006.022137e+26

Frequently asked questions

How many atomic mass unit is 1 gram?
1 gram equals 6.022137e+23 atomic mass unit.
How do I convert grams to atomic mass unit?
Multiply the value in grams by 6.022137e+23 to get atomic mass unit.
How do I convert atomic mass unit back to grams?
Multiply the value in atomic mass unit by 1.66054e-24, or use the Atomic Mass Unit to Gram converter.
How many atomic mass unit is 100 grams?
100 grams equals 6.022137e+25 atomic mass unit, because 100 × 6.022137e+23 = 6.022137e+25.

Convert Gram to other weight units

Show all Gram conversions
Metric / SI (17 units)
Gram to Attogram (ag) Gram to Femtogram (fg) Gram to Picogram (pg) Gram to Nanogram (ng) Gram to Microgram (µg) Gram to Milligram (mg) Gram to Centigram (cg) Gram to Decigram (dg) Gram to Dekagram (dag) Gram to Hectogram (hg) Gram to Kilogram (kg) Gram to Quintal (metric) (q) Gram to Metric Ton (t) Gram to Gigagram (Gg) Gram to Teragram (Tg) Gram to Petagram (Pg) Gram to Exagram (Eg)
Avoirdupois (15 units)
Gram to Grain (gr) Gram to Dram (avoirdupois) (dr) Gram to Ounce (oz) Gram to Pound (lb) Gram to Clove (clove) Gram to Stone (US) (st) Gram to Stone (UK) (st) Gram to Quarter (US) (qr) Gram to Quarter (UK) (qr) Gram to Hundredweight (US) (cwt) Gram to Hundredweight (UK) (cwt) Gram to Wey (wey) Gram to Kilopound (kip) (kip) Gram to Ton (short, US) (sh tn) Gram to Ton (long, UK) (long tn)
Troy & Apothecary (10 units)
Gram to Point (1/100 carat) (pt) Gram to Carat (metric) (ct) Gram to Scruple (apothecary) (s ap) Gram to Pennyweight (dwt) Gram to Momme (mom) Gram to Mace (mace) Gram to Dram (apothecary/troy) (dr ap) Gram to Troy Ounce (oz t) Gram to Tael (tael) Gram to Pound (troy/apothecary) (lb t)
Indian / South Asian (6 units)
Gram to Ratti (ratti) Gram to Masha (masha) Gram to Tola (tola) Gram to Chittack (Chatank) (chittack) Gram to Seer (Ser) (seer) Gram to Maund (Mann) (maund)
Scientific / Atomic (9 units)
Gram to Electron Mass (rest) (me) Gram to MeV/c2 (MeV/c²) Gram to Muon Mass (mµ) Gram to Atomic Mass Unit (u) Gram to Proton Mass (mp) Gram to Neutron Mass (mn) Gram to Deuteron Mass (md) Gram to Carbon-12 Atom Mass (C-12) Gram to Planck Mass (mP)
Astronomical (4 units)
Gram to Lunar Mass (Moon) (M☾) Gram to Earth's Mass (M⊕) Gram to Jupiter Mass (MJ) Gram to Sun's Mass (M☉)
Biblical / Ancient (14 units)
Gram to Lepton (Biblical Roman) (lepton) Gram to Quadrans (Biblical Roman) (quadrans) Gram to Assarion (Biblical Roman) (assarion) Gram to Gerah (Biblical Hebrew) (gerah) Gram to Drachma (Biblical Greek) (drachma) Gram to Denarius (Biblical Roman) (denarius) Gram to Bekan (Biblical Hebrew) (bekah) Gram to Didrachma (Biblical Greek) (didrachma) Gram to Shekel (Biblical Hebrew) (shekel) Gram to Tetradrachma (Biblical Greek) (tetra) Gram to Mina (Biblical Greek) (mina) Gram to Mina (Biblical Hebrew) (mina) Gram to Talent (Biblical Greek) (talent) Gram to Talent (Biblical Hebrew) (talent)
Force / Engineering (5 units)
Gram to Poundal (pdl) Gram to Ton (assay) (US) (AT) Gram to Ton (assay) (UK) (AT) Gram to Kilogram-force square second/meter (hyl) Gram to Slug (slug)

Sources & references

Conversion factor (1 g = 6.022137e+23 u) verified against the following authoritative sources:

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