Attogram is 1e-18 gram units.
Attograms to Grains Converter — ag to gr
Convert Attogram (ag) to Grain (gr) using the exact conversion factor (1 attogram = 1.543236e-17 grain). See the formula, worked examples, conversion table, history, and common uses.
Attograms to Grains 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.
A grain is exactly 64.79891 milligrams.
Result = input x 1e-21 / 6.479891e-5.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Attograms to Grains
Weight conversions between Attogram and Grain 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. Attogram is most often used for nanotechnology and single-molecule mass measurement.
Formula
grains = attograms × 1.543236e-17
This factor comes from each unit's defined relationship to the category's base unit: 1 attogram equals 1e-21 base units, and 1 grain equals 0.00006479891 base units, so dividing one by the other gives the direct attogram-to-grain factor of 1.543236e-17.
Simple example
1 ag × 1.543236e-17 = 1.543236e-17 gr
1 attogram = 1.543236e-17 grains.
Real-world example
50 ag × 1.543236e-17 = 7.716179e-16 gr
50 attograms = 7.716179e-16 grains.
Conversion table
| Attogram (ag) | Grain (gr) |
|---|---|
| 1 ag | 1.543236e-17 gr |
| 5 ag | 7.716179e-17 gr |
| 10 ag | 1.543236e-16 gr |
| 25 ag | 3.85809e-16 gr |
| 50 ag | 7.716179e-16 gr |
| 100 ag | 1.543236e-15 gr |
Reverse conversion: Grain to Attogram
1.543236e-17 gr × 6.479891e+16 = 1.000000107 ag
1.543236e-17 grains = 1.000000107 attograms.
attograms = grains × 6.479891e+16
For a page dedicated to this direction, see Grain to Attogram.
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.
Understanding the Grain (gr)
A grain is exactly 64.79891 milligrams.
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 grains are in 1 attogram?
1 attogram equals 1.543236e-17 grains, using the exact defined conversion factor rather than an estimate.
How do I convert attogram to grain?
Multiply the attogram value by 1.543236e-17. The converter above does this instantly to whatever precision you set.
How do I convert grain back to attogram?
Use the reverse factor: 1 grain equals 6.479891e+16 attograms. You can also use the swap control in the converter above to flip the direction instantly.
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.
What is a grain?
Grain (gr) is a unit of mass/weight.
Is the attogram to grain conversion exact?
Yes. Both attogram and grain are defined by fixed standards rather than physical artifacts, so the factor of 1.543236e-17 used above is exact to as many digits as you choose to display.
Where is the attogram still used today?
Used in specialized scientific measurement, not everyday contexts