What is stone?
A stone is a unit of mass used primarily in the United Kingdom and Ireland, equal to 14 pounds. It is mainly used to express human body weight in everyday conversation.
Real-world uses
The stone is used primarily in the UK and Ireland for expressing body weight (e.g., "I weigh 11 stone"). It appears on bathroom scales sold in Britain and is the preferred unit in British medical consultations for patient weight discussions.
History
The stone has been used in the British Isles since at least the 14th century for weighing agricultural goods. Its value varied historically (from 4 to 32 pounds depending on the commodity) before being fixed at 14 pounds by the Weights and Measures Act of 1835.
Common mistakes
Assuming a stone is used outside the British Isles—it is virtually unknown in the US, continental Europe, or most other countries. Also, forgetting that 1 stone = 14 pounds, not 10 or 12.
What is long ton (UK)?
A long ton is a unit of mass historically used in the United Kingdom, equal to 2,240 pounds. It is used in shipping, naval architecture, and some industrial contexts in the UK.
Real-world uses
The long ton was historically used in British shipping, coal mining, and iron/steel trade. Naval vessel displacement is sometimes still quoted in long tons. It occasionally appears in older British engineering specifications and historical trade records.
History
The long ton of 2,240 pounds derives from the traditional English system of 20 hundredweight (each 112 lb). It was the standard British ton until metrication in the 1970s largely replaced it with the metric tonne in commerce.
Common mistakes
Confusing the long ton (2,240 lb / 1,016 kg) with the short ton (2,000 lb / 907 kg) or the metric tonne (2,205 lb / 1,000 kg). This 12% difference can cause major commercial discrepancies.
When is this conversion used?
Converting stone to long ton (UK) is useful in the mass domain when comparing values across different measurement standards or applying formulas that require a specific unit.
Worked examples
1 stone = 0.00625 long ton (UK)
1 long ton (UK) = 1,016.0469088 kilogram
How to convert stone to long ton (UK)
To convert stone to long ton (UK), multiply the value by 0.00625.
To convert long ton (UK) back to stone, multiply by 160.
Measurement standards
The kilogram is defined by fixing the Planck constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds, as established at the 26th General Conference on Weights and Measures in 2018. This ended the last SI definition based on a physical artefact.
Did you know?
The International Prototype of the Kilogram, a platinum-iridium cylinder stored near Paris since 1889, was found to have drifted by about 50 micrograms relative to its copies over a century — roughly the mass of a fingerprint.
Quick reference: stone to long ton (UK)
| stone | long ton (UK) |
|---|---|
| 0.1 | 0.000625 |
| 0.5 | 0.003125 |
| 1 | 0.00625 |
| 2 | 0.0125 |
| 5 | 0.03125 |
| 10 | 0.0625 |
| 25 | 0.15625 |
| 50 | 0.3125 |
| 100 | 0.625 |
| 250 | 1.5625 |
| 500 | 3.125 |
| 1,000 | 6.25 |
Common values
| stone | long ton (UK) | |
|---|---|---|
| A paperclip | 0.15747304 stone | 0.00098421 long ton (UK) |
| A smartphone | 27.55778277 stone | 0.17223614 long ton (UK) |
| A bag of sugar | 0.15747304 stone | 0.00098421 long ton (UK) |
| Average adult human | 11.02311311 stone | 0.06889446 long ton (UK) |
| A small car | 188.9676533 stone | 1.18104783 long ton (UK) |