Unit Converters

Atomic Mass Units to Grams Converter

Atomic mass units

u → g

1.9926e-23 g

12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

You typed
12 u
One g is
6.0221e23 u
How it’s calculated
grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

Atomic mass units to Grams conversion table

Common u values in g. Same factor as the converter above: grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

Atomic mass units to Grams chart
Atomic mass unitsGrams
0.25 u4.1513e-25 g
0.5 u8.3027e-25 g
1 u1.6605e-24 g
2 u3.3211e-24 g
5 u8.3027e-24 g
10 u1.6605e-23 g
12 u1.9926e-23 g
18 u2.9890e-23 g
20 u3.3211e-23 g
25 u4.1513e-23 g
50 u8.3027e-23 g
100 u1.6605e-22 g

Plain-English guide

Terms & how it works

Confused by a field? Read the short definitions here while you use the tool.

  • Atomic mass units

    The “Atomic mass units” value used in this tool’s formula. Adjust it to see results update live.

grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

Daltons (u) are how chemists weigh atoms. Carbon-12 is defined as 12 u. The gram is 6.022 × 10²³ of those, which is why a mole of carbon is 12 g. This page is for lab sheets, not grocery bags.

How this calculator works

Daltons (u) are how chemists weigh atoms. Carbon-12 is defined as 12 u. The gram is 6.022 × 10²³ of those, which is why a mole of carbon is 12 g. This page is for lab sheets, not grocery bags. grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.) Scenario: 12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

Scenario: 12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

When to use this Atomic Mass Units to Grams

Common use cases

  • Daltons (u) are how chemists weigh atoms. Carbon-12 is defined as 12 u. The gram is 6.022 × 10²³ of those, which is why a mole of carbon is 12 g. This page is for lab sheets, not grocery bags.
  • Sanity-check with this scenario: 12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.
  • The relationship is: grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

Localized examples

  • Unit Converters: the example on this page uses the same formula as the widget.

What you get

  • Fields: Atomic mass units
  • grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)
  • Scenario on the page: 12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

How to Convert Atomic Mass Units to Grams

  1. 1Enter Atomic mass units. Use the values you have, not a catalog average, unless that is all you know.
  2. 2grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)
  3. 3Scenario: 12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.
  4. 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.

Governing formula

grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)

12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

12 u (carbon-12 atom) ≈ 1.993 × 10⁻²³ g. Water 18 u ≈ 2.989 × 10⁻²³ g per molecule.

Variable definitions

  • value

    Atomic mass units

    The “Atomic mass units” field. Default 12; typical range 0–1000000000.

  • The conversion (grams = u × 1.66053906660 × 10⁻²⁴. (1 u = 1.66053906660 × 10⁻²⁷ kg.)) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
  • Nothing here is uploaded for the calculation itself.

Frequently Asked Questions

Dalton and unified atomic mass unit are treated as the same here.

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4.8

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4 reviews

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Aisha K.

Mar 12, 2026

Clean layout and the results update instantly. Exactly what I needed for a quick planning check.

Daniel R.

Feb 28, 2026

Very usable on mobile. Would love a save/export option later, but the math feels solid.

Priya S.

Feb 3, 2026

The FAQ section answered my questions before I even had to search. Smooth dark mode too.

Marcus L.

Jan 19, 2026

Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.

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