A stone is 14 pounds.
Stones to Attograms Converter — st to ag
Convert Stone (st) to Attogram (ag) using the exact conversion factor (1 stone = 6.350293e+21 attogram). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Stones 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 6.35029318 / 1e-21.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Stones to Attograms
Weight conversions between Stone 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. Stone is typically associated with united Kingdom and Ireland (body weight), while Attogram is typically associated with used in specialized scientific measurement, not everyday contexts.
Formula
attograms = stones × 6.350293e+21
This factor comes from each unit's defined relationship to the category's base unit: 1 stone equals 6.35029318 base units, and 1 attogram equals 1e-21 base units, so dividing one by the other gives the direct stone-to-attogram factor of 6.350293e+21.
Simple example
1 st × 6.350293e+21 = 6.350293e+21 ag
1 stone = 6.350293e+21 attograms.
Real-world example
50 st × 6.350293e+21 = 3.175147e+23 ag
50 stones = 3.175147e+23 attograms.
Conversion table
| Stone (st) | Attogram (ag) |
|---|---|
| 1 st | 6.350293e+21 ag |
| 5 st | 3.175147e+22 ag |
| 10 st | 6.350293e+22 ag |
| 25 st | 1.587573e+23 ag |
| 50 st | 3.175147e+23 ag |
| 100 st | 6.350293e+23 ag |
Reverse conversion: Attogram to Stone
6.350293e+21 ag × 1.57473e-22 = 0.9999999717 st
6.350293e+21 attograms = 0.9999999717 stones.
stones = attograms × 1.57473e-22
For a page dedicated to this direction, see Attogram to Stone.
Stone vs. Attogram
| Aspect | Stone | Attogram |
|---|---|---|
| Family | UK customary unit | SI derived (metric prefix) unit |
| Typical use | Body weight reporting in the UK and Ireland (e.g. '12 stone 5 pounds') | Nanotechnology and single-molecule mass measurement |
| Where it's used | United Kingdom and Ireland (body weight) | Used in specialized scientific measurement, not everyday contexts |
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.
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.
Stone — sources
- UK Weights and Measures Act 1985 — Confirms the stone (14 lb) as a legally recognized UK unit for body weight.
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 stone?
1 stone equals 6.350293e+21 attograms, using the exact defined conversion factor rather than an estimate.
How do I convert stone to attogram?
Multiply the stone value by 6.350293e+21. The converter above does this instantly to whatever precision you set.
How do I convert attogram back to stone?
Use the reverse factor: 1 attogram equals 1.57473e-22 stones. You can also use the swap control in the converter above to flip the direction instantly.
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.
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 stone to attogram 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 stone still used today?
United Kingdom and Ireland (body weight)