Stone vs KG: Which Should You Use?
An honest comparison of precision, psychology, and practicality for UK bathroom scales.
The Honest Summary
There is no medical reason to prefer one over the other. Your scale measures the same mass either way; only the display changes. The real differences are psychological and practical: stone feels human, kilograms feel precise.
| Aspect | Stone | Kilograms | Edge |
|---|---|---|---|
| Precision | Stone + pounds (14 lb steps with lb remainder) | Kilogram + grams (finer granularity) | KG |
| Everyday UK use | Default for body weight in conversation | Used in gyms, apps, and medical settings | Stone |
| Medical records | Converted to kg by staff | Official NHS unit | KG |
| Motivation | 'Half a stone' feels like a milestone | Numbers feel abstract to many | Stone |
| International | UK and Ireland only | Universal worldwide | KG |
| Mental maths | 14x table takes practice | Decimal, easy to scale | KG |
The Case for Stone
Stone wins on human factors. Body weights in stone are compact two-part numbers: "11 stone 6". Milestones feel meaningful: half a stone (7 lb) is a satisfying chunk of progress, and a stone (14 lb) is a transformation. In kilograms, the same milestones are 3.2 kg and 6.35 kg, numbers that carry no cultural weight.
Stone also matches how Britons actually talk. Telling your partner you weigh "72 kilos" in the UK invites a blank look; "11 stone 5" is instantly understood. Social accountability, from Slimming World groups to family chats, runs on stone.
The Case for Kilograms
Kilograms win on precision and universality. A kilogram is a smaller unit than a stone, so daily fluctuations show up more clearly. Every medical system, fitness app, and scientific paper uses kg. If you travel, track macros with international apps, or discuss weight with a doctor, kilograms remove a conversion step.
Kilograms are also simpler arithmetic: decimal-based, no 14-times-table required.
The Practical Answer: Use Both
Most successful UK dieters do exactly this: track in stone, convert for official purposes. Set your scales to stone for daily motivation, and use a converter when your GP, an app, or a dosage calculator needs kilograms.
Keep these tools bookmarked: the stone to kg converter, the kg to stone converter, and the ideal weight chart in stone to see your healthy range in whichever unit you prefer.
Frequently Asked Questions
Is it better to weigh yourself in stone or kg?
For tracking trends, either works. Stone gives friendlier milestone numbers (half a stone, a stone), while kg gives finer precision and matches medical records. Many people track in stone and convert for the doctor.
Is kg more accurate than stone?
Slightly. Kilograms are a smaller unit (1 kg vs 14 lb per stone), so kg readings show smaller changes. But modern digital scales measure precisely regardless of the display unit.
Do UK doctors prefer kg?
Yes. The NHS records weight in kilograms. But clinicians routinely convert to stone when talking to patients, because that is the unit patients understand.
Why does stone feel more motivating for weight loss?
Psychology. 'Losing half a stone' sounds like a real achievement; 'losing 3.2 kg' sounds clinical. Round milestones in stone map well to how humans perceive progress.
How do I convert between stone and kg?
Multiply stone by 6.35029 to get kg. Divide kg by 6.35029 to get stone. Or use our free converters for instant results.