A troy ounce is exactly 31.1034768 grams.
Troy ounces to Atomic mass units Converter — oz t to u
Convert Troy ounce (oz t) to Atomic mass unit (u) using the exact conversion factor (1 troy ounce = 1.873095e+25 atomic mass unit). See the formula, worked examples, conversion table, history, and common uses.
Troy ounces to Atomic mass units converter
Converter
Mass/Weight Converter
Convert SI mass, imperial weight, jewelry, atomic, and astronomy mass units.
Context values
Some unit families need one extra value for a physically accurate result.
The unified atomic mass unit is used in atomic physics.
Result = input x 0.0311034768 / 1.66053907e-27.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Troy ounces to Atomic mass units
Weight conversions between Troy ounce and Atomic mass unit 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. Specifically: A troy ounce is exactly 31.1034768 grams, and the unified atomic mass unit is used in atomic physics.
Formula
atomic mass units = troy ounces × 1.873095e+25
This factor comes from each unit's defined relationship to the category's base unit: 1 troy ounce equals 0.0311034768 base units, and 1 atomic mass unit equals 1.660539e-27 base units, so dividing one by the other gives the direct troy ounce-to-atomic mass unit factor of 1.873095e+25.
Simple example
1 oz t × 1.873095e+25 = 1.873095e+25 u
1 troy ounce = 1.873095e+25 atomic mass units.
Real-world example
50 oz t × 1.873095e+25 = 9.365476e+26 u
50 troy ounces = 9.365476e+26 atomic mass units.
Conversion table
| Troy ounce (oz t) | Atomic mass unit (u) |
|---|---|
| 1 oz t | 1.873095e+25 u |
| 5 oz t | 9.365476e+25 u |
| 10 oz t | 1.873095e+26 u |
| 25 oz t | 4.682738e+26 u |
| 50 oz t | 9.365476e+26 u |
| 100 oz t | 1.873095e+27 u |
Reverse conversion: Atomic mass unit to Troy ounce
1.873095e+25 u × 5.338757e-26 = 0.9999999174 oz t
1.873095e+25 atomic mass units = 0.9999999174 troy ounces.
troy ounces = atomic mass units × 5.338757e-26
For a page dedicated to this direction, see Atomic mass unit to Troy ounce.
Understanding the Troy ounce (oz t)
A troy ounce is exactly 31.1034768 grams.
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.
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.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many atomic mass units are in 1 troy ounce?
1 troy ounce equals 1.873095e+25 atomic mass units, using the exact defined conversion factor rather than an estimate.
How do I convert troy ounce to atomic mass unit?
Multiply the troy ounce value by 1.873095e+25. The converter above does this instantly to whatever precision you set.
How do I convert atomic mass unit back to troy ounce?
Use the reverse factor: 1 atomic mass unit equals 5.338757e-26 troy ounces. You can also use the swap control in the converter above to flip the direction instantly.
What is a troy ounce?
Troy ounce (oz t) is a unit of mass/weight.
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).
Is the troy ounce to atomic mass unit 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.