An avoirdupois dram is 1/16 ounce.
Drams to Attograms Converter — dr to ag
Convert Dram (dr) to Attogram (ag) using the exact conversion factor (1 dram = 1.771845e+18 attogram). See the formula, worked examples, conversion table, history, and common uses.
Drams to Attograms converter
Converter
Mass/Weight Converter
Convert SI mass, imperial weight, jewelry, atomic, and astronomy mass units.
Context values
Some unit families need one extra value for a physically accurate result.
Attogram is 1e-18 gram units.
Result = input x 0.001771845195 / 1e-21.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Drams to Attograms
Weight conversions between Dram and Attogram 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. Specifically: An avoirdupois dram is 1/16 ounce, and attogram is 1e-18 gram units.
Formula
attograms = drams × 1.771845e+18
This factor comes from each unit's defined relationship to the category's base unit: 1 dram equals 0.00177184519531 base units, and 1 attogram equals 1e-21 base units, so dividing one by the other gives the direct dram-to-attogram factor of 1.771845e+18.
Simple example
1 dr × 1.771845e+18 = 1.771845e+18 ag
1 dram = 1.771845e+18 attograms.
Real-world example
50 dr × 1.771845e+18 = 8.859226e+19 ag
50 drams = 8.859226e+19 attograms.
Conversion table
| Dram (dr) | Attogram (ag) |
|---|---|
| 1 dr | 1.771845e+18 ag |
| 5 dr | 8.859226e+18 ag |
| 10 dr | 1.771845e+19 ag |
| 25 dr | 4.429613e+19 ag |
| 50 dr | 8.859226e+19 ag |
| 100 dr | 1.771845e+20 ag |
Reverse conversion: Attogram to Dram
1.771845e+18 ag × 5.643834e-19 = 0.9999998898 dr
1.771845e+18 attograms = 0.9999998898 drams.
drams = attograms × 5.643834e-19
For a page dedicated to this direction, see Attogram to Dram.
Understanding the Dram (dr)
An avoirdupois dram is 1/16 ounce.
Understanding the Attogram
Attogram (ag) measures mass. An attogram is 10⁻¹⁸ grams (10⁻²¹ kilograms) — 'atto-' is the SI prefix for one quintillionth. It is classified as a SI derived (metric prefix) unit.
Where it's used: Used in specialized scientific measurement, not everyday contexts
Uses of the Attogram today
- Nanotechnology and single-molecule mass measurement
- Analytical chemistry at extremely small mass scales
- Comparing against atomic-scale mass units like the atomic mass unit
History of the Attogram
The attogram is simply the gram combined with the SI prefix 'atto-' (10⁻¹⁸), one of the small-scale metric prefixes introduced by the International Committee for Weights and Measures as part of the broader SI prefix system, not a unit with its own separate history.
Historical origin. Attogram was not the invention of a single named person; it developed through the process described above.
Attogram — sources
- BIPM SI Brochure — SI prefixes — Defines 'atto-' as the prefix for 10⁻¹⁸.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many attograms are in 1 dram?
1 dram equals 1.771845e+18 attograms, using the exact defined conversion factor rather than an estimate.
How do I convert dram to attogram?
Multiply the dram value by 1.771845e+18. The converter above does this instantly to whatever precision you set.
How do I convert attogram back to dram?
Use the reverse factor: 1 attogram equals 5.643834e-19 drams. You can also use the swap control in the converter above to flip the direction instantly.
What is a dram?
Dram (dr) is a unit of mass/weight.
What is a attogram?
Attogram (ag) measures mass. An attogram is 10⁻¹⁸ grams (10⁻²¹ kilograms) — 'atto-' is the SI prefix for one quintillionth. It is classified as a SI derived (metric prefix) unit.
Is the dram to attogram conversion exact?
Yes. Both dram and attogram are defined by fixed standards rather than physical artifacts, so the factor of 1.771845e+18 used above is exact to as many digits as you choose to display.