How many drams are in 1 atomic mass unit?

1 atomic mass unit equals 9.371807e-25 drams, using the exact defined conversion factor rather than an estimate.

How do I convert atomic mass unit to dram?

Multiply the atomic mass unit value by 9.371807e-25. The converter above does this instantly to whatever precision you set.

How do I convert dram back to atomic mass unit?

Use the reverse factor: 1 dram equals 1.06703e+24 atomic mass units. You can also use the swap control in the converter above to flip the direction instantly.

Dram (dr) is a unit of mass/weight.

Is the atomic mass unit to dram conversion exact?

Yes. The unified atomic mass unit is defined as exactly 1/12 the mass of a carbon-12 atom, approximately 1.6605390666 × 10⁻²⁷ kg. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.

Atomic mass units to Drams Converter

Q: What is a atomic mass unit?

Atomic mass unit (u) measures mass. The unified atomic mass unit is defined as exactly 1/12 the mass of a carbon-12 atom, approximately 1.6605390666 × 10⁻²⁷ kg. It is classified as a Non-SI unit accepted for use with SI (scientific).

About Converting Atomic mass units to Drams

Weight conversions between Atomic mass unit and Dram come up constantly in everyday commerce, shipping, and cooking, since US packaging is usually labeled in pounds while most of the rest of the world uses kilograms. Atomic mass unit is most often used for expressing atomic and molecular masses in chemistry.

Formula

drams = atomic mass units × 9.371807e-25

This factor comes from each unit's defined relationship to the category's base unit: 1 atomic mass unit equals 1.660539e-27 base units, and 1 dram equals 0.00177184519531 base units, so dividing one by the other gives the direct atomic mass unit-to-dram factor of 9.371807e-25.

Simple example

1 u × 9.371807e-25 = 9.371807e-25 dr

1 atomic mass unit = 9.371807e-25 drams.

Real-world example

50 u × 9.371807e-25 = 4.685903e-23 dr

50 atomic mass units = 4.685903e-23 drams.

Conversion table

Atomic mass unit (u)	Dram (dr)
1 u	9.371807e-25 dr
5 u	4.685903e-24 dr
10 u	9.371807e-24 dr
25 u	2.342952e-23 dr
50 u	4.685903e-23 dr
100 u	9.371807e-23 dr

Reverse conversion: Dram to Atomic mass unit

9.371807e-25 dr × 1.06703e+24 = 1.000000032 u

9.371807e-25 drams = 1.000000032 atomic mass units.

atomic mass units = drams × 1.06703e+24

For a page dedicated to this direction, see Dram to Atomic mass unit.

Understanding the Atomic mass unit

Atomic mass unit (u) measures mass. The unified atomic mass unit is defined as exactly 1/12 the mass of a carbon-12 atom, approximately 1.6605390666 × 10⁻²⁷ kg. It is classified as a Non-SI unit accepted for use with SI (scientific).

Where it's used: Used internationally in chemistry and physics, not a general-public unit

Uses of the Atomic mass unit today

Expressing atomic and molecular masses in chemistry
Nuclear and particle physics mass calculations
Molecular weight tables and mass spectrometry

History of the Atomic mass unit

Atomic mass scales existed before international standardization, using either oxygen-16 or natural oxygen as a reference. In 1961, the International Union of Pure and Applied Chemistry (IUPAC) and physicists agreed on a unified scale based on carbon-12, ending decades of divergent chemistry and physics mass scales.

The unified atomic mass unit (u), also called the dalton (Da) in SI-adjacent contexts, is now tied to the carbon-12 standard and remains the base unit for atomic and molecular mass tables used across chemistry and physics.

Historical origin. Atomic mass unit was not the invention of a single named person; it developed through the process described above.

Understanding the Dram (dr)

An avoirdupois dram is 1/16 ounce.

Atomic mass unit — sources

BIPM SI Brochure — Non-SI units accepted for use with SI — Lists the unified atomic mass unit and its carbon-12 definition.

Atomic mass units to Drams Converter — u to dr

Mass/Weight Converter