✏️ Style Guide
The Stone Abbreviation: St
The abbreviation for stone is st. But the plural is where people trip up: it is "11 stone" when you weigh yourself, and "stones" everywhere else. This guide settles it.
The Symbol: St
The recognised abbreviation for the stone is st, listed in dictionaries including Collins. It sits alongside lb for pound and oz for ounce in the family of imperial abbreviations. Unlike kg, which is an official SI symbol, st is a customary abbreviation, but it is universally understood in Britain and Ireland.
Style points: write it in lower case (st, not ST), with no full stop in modern usage (st, not st.), and with no space between the number and the abbreviation when space is tight (11st), though "11 st" is also acceptable. Our converters use the compact form: try the stone to pounds converter.
Stone vs Stones: The Two Plurals
This is the question that brings most people here, and the answer is genuinely two rules, not one. The stone has an invariant plural in one specific context and a regular plural everywhere else:
| Context | Correct form | Example |
|---|---|---|
| Stating a person's weight | stone (no s) | "I weigh 11 stone" |
| Stone-and-pounds weight | stone (no s) | "12 stone 6 pounds" |
| General / formal writing | stones | "Enter weight in stones and pounds" |
| Counting units abstractly | stones | "A hundredweight is 8 stones" |
Why the split? When you say "11 stone," the word is functioning almost like an adjective describing the weight, similar to "a 6 foot man" (not "6 feet man"). In formal or technical writing, the ordinary plural "stones" applies. Neither is wrong in the wrong place exactly, but using the right one marks you as someone who knows the unit.
How to Write Stone and Pounds
The standard format puts stone first, then the leftover pounds:
- Compact: 11st 6lb
- Words: 11 stone 6 pounds
- Mixed: 11st 6 pounds (common in journalism)
Two rules keep it tidy. First, the pounds figure is always below 14: "11 stone 14 pounds" is wrong, because 14 pounds is another stone (write "12 stone"). Second, do not use decimal stone in formal writing; "11.4 stone" is understood conversationally but "11 stone 6 pounds" is clearer and standard. For the maths behind the format, see stone to pounds.
Common mistakes to avoid: "11 stones 6 pounds" when describing a person (drop the s), "11st. 6lbs." with full stops (modern style omits them), and "11 stone and 6 pound" (pounds takes the s). Get these right and your writing looks native.
Frequently Asked Questions
What is the abbreviation for stone?
The abbreviation for stone is st. For example, 11 stone 6 pounds is written 11st 6lb.
Is the plural of stone 'stone' or 'stones'?
Both, depending on context. When stating body weight, the plural is stone: '11 stone', '12 stone 6 pounds'. In other contexts, such as forms asking for weight, the regular plural stones is correct: 'enter your weight in stones and pounds'.
How do you write stone and pounds correctly?
Write the stone figure first, then the remaining pounds: 11st 6lb, or in words, 11 stone 6 pounds. The pounds figure is always less than 14, because 14 pounds would be another stone.
Does 'st' need a full stop?
Modern style omits it: st, not st. Dictionaries list both st and st., but current British usage favours st without the point, matching kg, lb, and other unit symbols.