An avoirdupois ounce is 1/16 pound.
Ounces to Drams Converter — oz to dr
Convert Ounce (oz) to Dram (dr) using the exact conversion factor (1 ounce = 16 dram). See the formula, worked examples, conversion table, history, and common uses.
Ounces to Drams converter
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An avoirdupois dram is 1/16 ounce.
Result = input x 0.02834952313 / 0.001771845195.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Ounces to Drams
Weight conversions between Ounce 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. Ounce is most often used for us cooking and recipe measurement (small quantities).
Formula
drams = ounces × 16
This factor comes from each unit's defined relationship to the category's base unit: 1 ounce equals 0.028349523125 base units, and 1 dram equals 0.00177184519531 base units, so dividing one by the other gives the direct ounce-to-dram factor of 16.
Simple example
1 oz × 16 = 16 dr
1 ounce = 16 drams.
Real-world example
50 oz × 16 = 800 dr
50 ounces = 800 drams.
Conversion table
| Ounce (oz) | Dram (dr) |
|---|---|
| 1 oz | 16 dr |
| 5 oz | 80 dr |
| 10 oz | 160 dr |
| 25 oz | 400 dr |
| 50 oz | 800 dr |
| 100 oz | 1,600 dr |
Reverse conversion: Dram to Ounce
16 dr × 0.0625 = 1 oz
16 drams = 1 ounce.
ounces = drams × 0.0625
For a page dedicated to this direction, see Dram to Ounce.
Understanding the Ounce
Ounce (oz) measures mass. The avoirdupois ounce is 1/16 of a pound: exactly 28.349523125 grams. It is classified as a US/imperial customary unit.
Where it's used: United States (cooking, postal, retail) United Kingdom (informal/retail use)
Avoirdupois ounce vs. troy ounce. The everyday ounce (avoirdupois, 28.35 g) used for cooking and shipping is a different, smaller unit than the troy ounce (31.10 g) used for precious metals like gold and silver — this page uses the everyday avoirdupois ounce.
Uses of the Ounce today
- US cooking and recipe measurement (small quantities)
- US postal and shipping weight
- Precious metals (troy ounce, a related but distinct unit)
History of the Ounce
The ounce descends from the Roman 'uncia' (a twelfth part), inherited through medieval English weight systems; the avoirdupois ounce (for general goods, as opposed to the troy ounce for precious metals) became standard for everyday trade, fixed at exactly 28.349523125 g via the pound's 1959 international standardization.
Historical origin. Ounce 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.
Ounce — sources
- NIST — International yard and pound (1959) — Basis for the modern ounce via the standardized pound.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many drams are in 1 ounce?
1 ounce equals 16 drams, using the exact defined conversion factor rather than an estimate.
How do I convert ounce to dram?
Multiply the ounce value by 16. The converter above does this instantly to whatever precision you set.
How do I convert dram back to ounce?
Use the reverse factor: 1 dram equals 0.0625 ounces. You can also use the swap control in the converter above to flip the direction instantly.
What is a ounce?
Ounce (oz) measures mass. The avoirdupois ounce is 1/16 of a pound: exactly 28.349523125 grams. It is classified as a US/imperial customary unit.
What is a dram?
Dram (dr) is a unit of mass/weight.
Is the ounce to dram conversion exact?
Yes. The avoirdupois ounce is 1/16 of a pound: exactly 28.349523125 grams. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between avoirdupois ounce vs. troy ounce?
The everyday ounce (avoirdupois, 28.35 g) used for cooking and shipping is a different, smaller unit than the troy ounce (31.10 g) used for precious metals like gold and silver — this page uses the everyday avoirdupois ounce.
Where is the ounce still used today?
United States (cooking, postal, retail) United Kingdom (informal/retail use)