Attogram is 1e-18 gram units.
Attograms to Stones Converter — ag to st
Convert Attogram (ag) to Stone (st) using the exact conversion factor (1 attogram = 1.57473e-22 stone). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Attograms to Stones 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 stone is 14 pounds.
Result = input x 1e-21 / 6.35029318.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Attograms to Stones
Weight conversions between Attogram and Stone 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 typically associated with used in specialized scientific measurement, not everyday contexts, while Stone is typically associated with united Kingdom and Ireland (body weight).
Formula
stones = attograms × 1.57473e-22
This factor comes from each unit's defined relationship to the category's base unit: 1 attogram equals 1e-21 base units, and 1 stone equals 6.35029318 base units, so dividing one by the other gives the direct attogram-to-stone factor of 1.57473e-22.
Simple example
1 ag × 1.57473e-22 = 1.57473e-22 st
1 attogram = 1.57473e-22 stones.
Real-world example
50 ag × 1.57473e-22 = 7.873652e-21 st
50 attograms = 7.873652e-21 stones.
Conversion table
| Attogram (ag) | Stone (st) |
|---|---|
| 1 ag | 1.57473e-22 st |
| 5 ag | 7.873652e-22 st |
| 10 ag | 1.57473e-21 st |
| 25 ag | 3.936826e-21 st |
| 50 ag | 7.873652e-21 st |
| 100 ag | 1.57473e-20 st |
Reverse conversion: Stone to Attogram
1.57473e-22 st × 6.350293e+21 = 0.9999997179 ag
1.57473e-22 stones = 0.9999997179 attograms.
attograms = stones × 6.350293e+21
For a page dedicated to this direction, see Stone to Attogram.
Attogram vs. Stone
| Aspect | Attogram | Stone |
|---|---|---|
| Family | SI derived (metric prefix) unit | UK customary unit |
| Typical use | Nanotechnology and single-molecule mass measurement | Body weight reporting in the UK and Ireland (e.g. '12 stone 5 pounds') |
| Where it's used | Used in specialized scientific measurement, not everyday contexts | United Kingdom and Ireland (body weight) |
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 Stone
Stone (st) measures mass. A stone is 14 pounds: exactly 6.35029318 kilograms. It is classified as a UK customary unit.
Where it's used: United Kingdom and Ireland (body weight)
Uses of the Stone today
- Body weight reporting in the UK and Ireland (e.g. '12 stone 5 pounds')
- Historical wool and agricultural produce weighing
History of the Stone
The stone dates to medieval England as a general-purpose weight unit, historically varying by region and commodity (a 'stone' of wool differed from a 'stone' of meat) before settling on 14 pounds for general use. It remains in everyday use for body weight in the UK and Ireland, unlike most other English customary units which have been replaced or supplemented by metric measures.
Historical origin. Stone 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.
Stone — sources
- UK Weights and Measures Act 1985 — Confirms the stone (14 lb) as a legally recognized UK unit for body weight.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many stones are in 1 attogram?
1 attogram equals 1.57473e-22 stones, using the exact defined conversion factor rather than an estimate.
How do I convert attogram to stone?
Multiply the attogram value by 1.57473e-22. The converter above does this instantly to whatever precision you set.
How do I convert stone back to attogram?
Use the reverse factor: 1 stone equals 6.350293e+21 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 stone?
Stone (st) measures mass. A stone is 14 pounds: exactly 6.35029318 kilograms. It is classified as a UK customary unit.
Is the attogram to stone conversion exact?
Yes. A stone is 14 pounds: exactly 6.35029318 kilograms. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the attogram still used today?
Used in specialized scientific measurement, not everyday contexts