Convert Pennyweight to Attogram
Convert pennyweights to attograms instantly. 1 pennyweight = 1.555174e+18 attogram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Attogram 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.
Attogram
An attogram (ag) equals 10^-21 kilogram.
From the SI prefix 'atto-' (from Danish 'atten', eighteen).
Frontier nanoscience and single-molecule mass detection.
The atto- prefix was adopted by the CGPM in 1975.
Pennyweight to Attogram conversion formula
The relationship between pennyweights and attograms:
To convert pennyweights to attograms, multiply the value in pennyweights by 1.555174e+18. To reverse, multiply attograms by 6.430149e-19.
How to use this converter
Type a value into the calculator. The result in attograms updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Attogram to Pennyweight converter for the reverse direction.
Step-by-step: convert pennyweights to attograms
- Write down the value in pennyweights (dwt).
- Multiply that value by the factor 1.555174e+18.
- The product is the equivalent value in attograms (ag).
- To reverse, multiply the attogram value by 6.430149e-19.
Worked examples
Example 1 — Convert 1 dwt to ag:
1 × 1.555174e+18 = 1.555174e+18 ag
Example 2 — Convert 100 dwt to ag:
100 × 1.555174e+18 = 1.555174e+20 ag
Real-world example — Small-scale to atomic-scale
One pennyweight equals 10 million attograms — useful for physics curricula that relate everyday measurements to atomic and optical scales.
1 dwt × 1.555174e+18 = 1.555174e+18 ag
Real-world example — Centimeter to wavelength scale
One pennyweight equals 10 million attograms. Physics curricula use this kind of conversion to relate everyday measurements to atomic and optical scales.
1 dwt × 1.555174e+18 = 1.555174e+18 ag
Pennyweight to Attogram conversion table
Standard reference values for converting pennyweights to attograms:
| Pennyweight [dwt] | Attogram [ag] |
|---|---|
| 0.01 | 1.555174e+16 |
| 0.1 | 1.555174e+17 |
| 1 | 1.555174e+18 |
| 2 | 3.110348e+18 |
| 3 | 4.665521e+18 |
| 4 | 6.220695e+18 |
| 5 | 7.775869e+18 |
| 10 | 1.555174e+19 |
| 20 | 3.110348e+19 |
| 30 | 4.665521e+19 |
| 40 | 6.220695e+19 |
| 50 | 7.775869e+19 |
| 100 | 1.555174e+20 |
| 500 | 7.775869e+20 |
| 1000 | 1.555174e+21 |
Frequently asked questions
How many attograms is 1 pennyweight?
How do I convert pennyweights to attograms?
How do I convert attograms back to pennyweights?
How many attograms 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 = 1.555174e+18 ag) 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.