Convert Ounce to Pennyweight
Convert ounces to pennyweights instantly. 1 ounce = 18.2291671195 pennyweight — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Pennyweight 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.
Pennyweight
The pennyweight (dwt) equals one-twentieth of a troy ounce, 24 grains (about 1.555 g).
From the mass of a medieval English silver penny; symbol dwt from 'denarius weight'.
Jewelry making and precious-metal scrap valuation in the US.
Derived from the medieval English coinage system.
Ounce to Pennyweight conversion formula
The relationship between ounces and pennyweights:
To convert ounces to pennyweights, multiply the value in ounces by 18.2291671195. To reverse, multiply pennyweights by 0.0548571415.
How to use this converter
Type a value into the calculator. The result in pennyweights updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Pennyweight to Ounce converter for the reverse direction.
Step-by-step: convert ounces to pennyweights
- Write down the value in ounces (oz).
- Multiply that value by the factor 18.2291671195.
- The product is the equivalent value in pennyweights (dwt).
- To reverse, multiply the pennyweight value by 0.0548571415.
Worked examples
Example 1 — Convert 1 oz to dwt:
1 × 18.2291671195 = 18.2291671195 dwt
Example 2 — Convert 100 oz to dwt:
100 × 18.2291671195 = 1822.9167119456 dwt
Real-world example — Postcard and small-object dimensions
A postcard is about 5 ounces wide. Converting to pennyweights is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 oz × 18.2291671195 = 91.1458355973 dwt
Real-world example — Ruler-scale measurements
A 30-ounce school ruler converts cleanly to pennyweights — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 oz × 18.2291671195 = 546.8750135837 dwt
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 pennyweights daily when mixing metric and imperial tools.
10 oz × 18.2291671195 = 182.2916711946 dwt
Ounce to Pennyweight conversion table
Standard reference values for converting ounces to pennyweights:
| Ounce [oz] | Pennyweight [dwt] |
|---|---|
| 0.01 | 0.1822916712 |
| 0.1 | 1.8229167119 |
| 1 | 18.2291671195 |
| 2 | 36.4583342389 |
| 3 | 54.6875013584 |
| 4 | 72.9166684778 |
| 5 | 91.1458355973 |
| 10 | 182.2916711946 |
| 20 | 364.5833423891 |
| 30 | 546.8750135837 |
| 40 | 729.1666847783 |
| 50 | 911.4583559728 |
| 100 | 1822.9167119456 |
| 500 | 9114.5835597282 |
| 1000 | 18229.1671194564 |
Frequently asked questions
How many pennyweights is 1 ounce?
How do I convert ounces to pennyweights?
How do I convert pennyweights back to ounces?
How many pennyweights 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 = 18.2291671195 dwt) 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 Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.