Convert Ounce to Dram (avoirdupois)
Convert ounces to drams (avoirdupois) instantly. 1 ounce = 15.9999999436 dram (avoirdupois) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Dram (avoirdupois) to Ounce converter for the reverse conversion.
Units explained
Ounce
The (avoirdupois) ounce (oz) equals one-sixteenth of a pound, about 28.35 grams.
From Latin 'uncia', meaning a twelfth part.
US food portions, postal weights, and boxing weight classes.
Standardized as 1/16 of the international pound from 1959.
Dram (avoirdupois)
The avoirdupois dram (dr) equals one-sixteenth of an ounce, about 1.77 grams.
From Greek 'drachma' through Latin 'dragma'.
Historically pharmacy; today occasional cooking and firearms (powder) use.
Defined as 1/256 of the avoirdupois pound.
Ounce to Dram (avoirdupois) conversion formula
The relationship between ounces and drams (avoirdupois):
To convert ounces to drams (avoirdupois), multiply the value in ounces by 15.9999999436. To reverse, multiply drams (avoirdupois) by 0.0625000002.
How to use this converter
Type a value into the calculator. The result in drams (avoirdupois) updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Dram (avoirdupois) to Ounce converter for the reverse direction.
Step-by-step: convert ounces to drams (avoirdupois)
- Write down the value in ounces (oz).
- Multiply that value by the factor 15.9999999436.
- The product is the equivalent value in drams (avoirdupois) (dr).
- To reverse, multiply the dram (avoirdupois) value by 0.0625000002.
Worked examples
Example 1 — Convert 1 oz to dr:
1 × 15.9999999436 = 15.9999999436 dr
Example 2 — Convert 100 oz to dr:
100 × 15.9999999436 = 1599.9999943562 dr
Real-world example — Postcard and small-object dimensions
A postcard is about 5 ounces wide. Converting to drams (avoirdupois) is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 oz × 15.9999999436 = 79.9999997178 dr
Real-world example — Ruler-scale measurements
A 30-ounce school ruler converts cleanly to drams (avoirdupois) — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 oz × 15.9999999436 = 479.9999983068 dr
Real-world example — Hardware-scale dimensions
A 10-ounce fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between ounces and drams (avoirdupois) daily when mixing metric and imperial tools.
10 oz × 15.9999999436 = 159.9999994356 dr
Ounce to Dram (avoirdupois) conversion table
Standard reference values for converting ounces to drams (avoirdupois):
| Ounce [oz] | Dram (avoirdupois) [dr] |
|---|---|
| 0.01 | 0.1599999994 |
| 0.1 | 1.5999999944 |
| 1 | 15.9999999436 |
| 2 | 31.9999998871 |
| 3 | 47.9999998307 |
| 4 | 63.9999997742 |
| 5 | 79.9999997178 |
| 10 | 159.9999994356 |
| 20 | 319.9999988712 |
| 30 | 479.9999983068 |
| 40 | 639.9999977425 |
| 50 | 799.9999971781 |
| 100 | 1599.9999943562 |
| 500 | 7999.9999717808 |
| 1000 | 15999.9999435617 |
Frequently asked questions
How many drams (avoirdupois) is 1 ounce?
How do I convert ounces to drams (avoirdupois)?
How do I convert drams (avoirdupois) back to ounces?
How many drams (avoirdupois) is 100 ounces?
Popular weight unit conversions
Convert Ounce to other weight units
Show all Ounce conversions
Metric / SI (18 units)
Avoirdupois (14 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 oz = 15.9999999436 dr) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.