Convert Pennyweight to Milligram
Convert pennyweights to milligrams instantly. 1 pennyweight = 1555.1738 milligram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Milligram to Pennyweight converter for the reverse conversion.
Units explained
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.
Milligram
A milligram (mg) equals one-millionth of a kilogram, or 0.001 gram.
From the SI prefix 'milli-' (from Latin 'mille', thousand).
Standard for medicine dosing, nutrition labels, and fine jewelry.
Part of the original metric system of 1795.
Pennyweight to Milligram conversion formula
The relationship between pennyweights and milligrams:
To convert pennyweights to milligrams, multiply the value in pennyweights by 1555.1738. To reverse, multiply milligrams by 0.0006430149.
How to use this converter
Type a value into the calculator. The result in milligrams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Milligram to Pennyweight converter for the reverse direction.
Step-by-step: convert pennyweights to milligrams
- Write down the value in pennyweights (dwt).
- Multiply that value by the factor 1555.1738.
- The product is the equivalent value in milligrams (mg).
- To reverse, multiply the milligram value by 0.0006430149.
Worked examples
Example 1 — Convert 1 dwt to mg:
1 × 1555.1738 = 1555.1738 mg
Example 2 — Convert 100 dwt to mg:
100 × 1555.1738 = 155517.38 mg
Real-world example — Adjacent small-scale precision
One pennyweight equals 1,000 milligrams — the standard sub-millimeter precision conversion that materials engineers use whenever they switch between bulk material thickness specs (larger unit) and surface-finish characteristics (smaller unit).
1 dwt × 1555.1738 = 1555.1738 mg
Real-world example — Adjacent metric sub-units
One pennyweight equals 1,000 milligrams. Engineers move between these scales constantly: PCB feature sizes in the larger unit, wire-bond diameters in the smaller.
1 dwt × 1555.1738 = 1555.1738 mg
Pennyweight to Milligram conversion table
Standard reference values for converting pennyweights to milligrams:
| Pennyweight [dwt] | Milligram [mg] |
|---|---|
| 0.01 | 15.551738 |
| 0.1 | 155.51738 |
| 1 | 1555.1738 |
| 2 | 3110.3476 |
| 3 | 4665.5214 |
| 4 | 6220.6952 |
| 5 | 7775.869 |
| 10 | 15551.738 |
| 20 | 31103.476 |
| 30 | 46655.214 |
| 40 | 62206.952 |
| 50 | 77758.69 |
| 100 | 155517.38 |
| 500 | 777586.9 |
| 1000 | 1555173.8 |
Frequently asked questions
How many milligrams is 1 pennyweight?
How do I convert pennyweights to milligrams?
How do I convert milligrams back to pennyweights?
How many milligrams is 100 pennyweights?
Popular weight unit conversions
Convert Pennyweight to other weight units
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Metric / SI (18 units)
Avoirdupois (15 units)
Troy & Apothecary (9 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 dwt = 1555.1738 mg) 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.