The stone is a traditional unit of weight widely used in the United Kingdom and Ireland. One stone is equal to 14 pounds or approximately 6.35 kilograms. But why specifically 14 pounds for a stone? The use of a “stone” as a unit of weight dates back centuries and has an interesting history behind it.
The origins of the stone as a unit of weight
The stone has been used as a unit of weight in England since at least the 13th century. Back then, a “stone weight” referred to the stone weights used on a balance scale to determine the weight of various commodities. These stone weights were literally made of stone, carved into round or rectangular shapes of varying sizes.
The specific weight of 14 pounds for a stone arose in 1389 during the reign of King Richard II. An English statute was enacted called the Composition of Yards and Perches, which legally defined a stone as being 14 pounds in weight. This statute helped standardize weights and measures across England at the time.
Prior to this, the exact weight of a “stone” was not well defined and could vary slightly from location to location. The 14 pound stone became the standardized, legal definition through this statute.
Use of stone weights on balance scales
Back in the medieval period when the stone was first used as a unit, balance scales were utilized to weigh goods and commodities. These scales used counterbalanced pans or plates. Standardized weights were placed on one side to counterbalance the item being weighed on the other.
Stone weights of varying sizes served as those standardized counterweights. The historical origins of the stone unit stem from these practical stone weights used for balances. Smaller stones weights included:
- 1/2 stone = 7 pounds
- 1 stone = 14 pounds
- 2 stone = 28 pounds
- 3 stone = 42 pounds
Larger stone weights went up from there in increments of 14 pounds. The sizes were practical for weighing everyday commodities like meat, produce, wool, and other products.
Adoption of the 14 pound stone as a unit
The use of stone weights on scales led to “stone” being adopted as an everyday unit of measurement for weight. And the most common weight used in trade and commerce at the time was the 14 pound stone.
So the practical need for a 14 pound counterweight on scales fueled its use. Since 14 pounds served as a convenient benchmark, people began referring to this amount as “one stone” for short. Thus, the stone became a standard unit equal to 14 pounds through convention and practical usage.
The stone in modern times
While no longer widely used for commercial weighing, the stone remains in common use as a unit of weight in Britain and Ireland today. For instance:
- Body weights are often measured in stone and pounds.
- Measurements in stone are common in sports like boxing and wrestling when classifying heavyweight competitors.
- Many British recipes still list ingredient quantities in stones and pounds.
The stone has endured as a traditional unit. Its longevity stems from those early stone weights used on balance scales centuries ago during the era when the 14 pound stone was standardized.
So in summary, the answer to why a stone is defined as 14 pounds traces back to the stone weights used historically for weighing goods. The practical need for a 14 pound counterweight led to this base unit being called “one stone” which stuck over the centuries.
Stone weights vs. metric system
The use of stone as a weight measurement is seen as archaic by some since most of the world has adopted the metric system for weights and measures. The stone is part of the imperial system of units which also includes pounds, ounces, and grains.
But in Britain and Ireland, stones remain entrenched in the culture and vernacular despite the metric system displacing many other imperial units over time. Stones are so ingrained that their use persists today, especially for body weight.
The table below shows some comparisons against metric units:
| Unit | Pounds | Kilograms |
|---|---|---|
| 1 stone | 14 lbs | 6.35 kg |
| 2 stone | 28 lbs | 12.7 kg |
| 3 stone | 42 lbs | 19.05 kg |
This demonstrates how the imperial stone translates into metric units. While not as precise, stones have the advantage of being smaller whole number increments. The stone has endured culturally despite the predominance of the metric system.
Is the stone still relevant today?
The continued use of the stone in modern times is sometimes debated. On the one hand, it is seen by some as antiquated and archaic compared to the metric system used almost universally around the world.
However, the stone remains firmly entrenched in British culture, especially for body weight. Generations have grown up with the stone as their traditional unit of measure. Some argue it is easier to visualize body weights in whole number stones rather than kilograms.
Stones are also ingrained in the vernacular. Expressions like “a good 10 stone” or “putting on half a stone” remain common. Sports like boxing and wrestling have weight classes traditionally measured in stones.
Given these factors, the stone remains relevant today as a traditional unit. It is interwoven into the culture, language, and practices around measuring body mass. The stone endures as a relic of a bygone era of weights and measures.
While some view it as an anachronism, its longevity demonstrates that the stone still has utility in modern life. The stone traces its roots back centuries to those early weights on balance scales. This history and context gives the stone its lasting place in British culture.
Decimalization efforts in the UK
Despite its enduring use, there have been efforts to move away from the stone and other imperial units in the United Kingdom. In 1965, the government mandated a transition toward metric units as part of broader decimalization efforts.
Decimal currency was also introduced at this time. Traditional currencies like pounds, shillings, and pence were replaced by a new decimal system of 100 pence to a pound.
Weights and measures decimalization was slower. Use of metric units, like grams and kilograms, increased in commercial and retail sectors. But stones remained in common use for body weight.
In 1985, the government adopted further mandates requiring increasing use of metric units. But again, the stone remained exempt, especially for body mass. This demonstrates how ingrained the stone is culturally.
Arguments for keeping the stone
There are several arguments for keeping the stone unit despite the broader move to metric:
- It is the traditional unit Britons understand, especially for body mass.
- Converting to metric could cause confusion, especially among older people used to imperial stones.
- The incremental stone scale makes sense for measuring bodies in whole numbers.
- Metric kilograms are not as convenient or personalized for expressing body weight.
Given these factors, the stone has resisted full metric conversion and hangs on as a traditional unit for weighing bodies in Britain and Ireland.
Arguments against the stone
Some make the case that the stone should be phased out in favor of metric units:
- It is inconsistent and confusing to use both metric and imperial systems.
- Metrification would align the UK with Europe and most of the world.
- The stone is imprecise compared to metric units.
- Retaining archaic units hampers young people’s understanding of modern metric measures.
Despite these arguments, there is still no plan to fully phase out the stone. It remains a fixture for body weight measurement in Britain and Ireland.
The stone and mental arithmetic
An interesting argument for keeping the stone unit is its potential benefits for mental arithmetic. Having a relatively small base unit of 14 pounds facilitates easier mental calculations.
Estimating, adding, subtracting and converting stones and pounds in one’s head is reasonably straightforward compared to metric kilograms. The built-in divisions of 14 pounds lend themselves well to mental math.
For example:
- 2 stone 7 pounds = 33 pounds
- 1 stone 8 pounds + 2 stone 4 pounds = 3 stone 12 pounds
- 17 pounds is roughly 1 stone 3 pounds
Doing similar mental math with kilograms would be more challenging. The incremental stone system is easier for approximation and arithmetic without a calculator.
This mental math argument is another reason some UK educators advocate keeping the stone around. It provides good practice for mental arithmetic skills, especially for school-aged children.
Is the stone’s future secure?
Given its centuries of use and entrenchment in British culture, the future of the stone unit seems fairly secure, at least for the near term. There are no active plans to phase it out or enact new decimalization mandates.
However, trends can change over generational timespans. Younger Britons are increasingly accustomed to metric units in most aspects of life. So weighing stones may gradually decline in usage over the coming decades.
But for now, the stone remains firmly rooted, especially for measuring body weight. Its long history and utility in mental math should ensure it stays relevant for the foreseeable future.
Conclusion
In summary, the stone as a unit of 14 pounds has its origins in the standardized stone counterweights used on balance scales in Medieval England. The 14 pound weight emerged as the most common “stone” in commerce and trade.
This led to the stone being adopted as a standardized unit of weight equal to 14 pounds. Despite decimalization efforts and the predominance of the metric system, the stone endures as a traditional unit of measure in Britain and Ireland.
Especially for expressing body weight, the stone is still widely used and valued. Its incremental nature lends itself well to mental arithmetic. Given its centuries of history and deep entrenchment culturally, the stone is likely to persist as a unit of weight into the foreseeable future.