GuidesStone Weight: UK Speech vs US Scales
Stone Weight: UK Speech vs US Scales
Convert British stone and pounds to kilograms and pounds, read UK body-weight phrases correctly, and avoid decimal-stone mistakes on forms.
By the Units Converters editorial team · Voyager Tecnologias LTDA
What a stone is
One stone equals exactly 14 avoirdupois pounds. Using the international pound, 1 stone = 6.35029318 kg. UK everyday speech still describes adult body weight in stone and pounds (“11 stone 4”), even though medical records increasingly prefer kilograms.
US bathroom scales and forms almost never use stone. If you move between the UK and US, you will translate between stone↔lb and stone↔kg often. Freight and science do not use stone—keep it in the body-weight and informal UK context.
Because 14 lb make a stone, leftover pounds always run from 0 to 13 in normal speech. Saying “11.4 stone” casually might mean 11 st 4 lb to a listener—or 11.4 × 14 lb to a spreadsheet. Those disagree. Prefer “11 st 4 lb” in writing.
Converting stone and pounds to kilograms
Method A: convert stone to pounds (× 14), add leftover pounds, convert total pounds to kilograms. Method B: convert stone to kilograms (× 6.35029318) and convert leftover pounds to kilograms (× 0.45359237), then add. Both match if you use exact factors.
Example: 11 st 4 lb → (11 × 14) + 4 = 158 lb → about 71.67 kg. Round for the form’s rules (often whole kilograms in casual contexts, one decimal in clinics).
Reverse: kilograms to stone for conversation—divide kg by 6.35029318 to get decimal stone, then split into whole stone and remaining pounds carefully—or convert kg → lb first, then divide by 14 for stone and remainder.
US pounds-only world
US friends and apps expect a single pound figure. Convert UK stone-and-pounds to total pounds before sharing. 11 st 4 lb = 158 lb, not “11.4 lb.” That error is an order of magnitude wrong and alarms health apps.
Gym programs written in pounds need working weights in pounds. Convert body weight only if the program indexes loads to body weight; otherwise convert the prescribed plate weights, not your nickname weight in stone.
Airline baggage is kilograms or pounds—not stone. Never put stone on a shipping label.
Medical and passport-adjacent forms
NHS-style contexts may accept stones and pounds or kilograms depending on the form. Enter exactly the format requested. If it wants kilograms, convert fully; do not type stone into a kg box.
Pediatric and athletic charts may use kilograms internationally. Convert once from a measured scale reading. Re-weigh rather than eternally converting an old stone value after training cycles.
When a US telehealth portal rejects a weight, check whether it expects lb and you typed kg (or the reverse). Unit mismatch looks like physiologically impossible input.
Mental anchors
10 st ≈ 63.5 kg ≈ 140 lb; 11 st ≈ 69.9 kg ≈ 154 lb; 12 st ≈ 76.2 kg ≈ 168 lb; 14 st ≈ 88.9 kg ≈ 196 lb. Anchors help conversation; exact converters help forms.
Half-stone changes (7 lb ≈ 3.2 kg) are common in fitness talk. Convert the change the same way you convert absolute weight.
If your scale shows kg but your coach talks stone, keep training logs in kilograms and convert only for the coach’s summary. One source of truth beats dual editing every session.
Workflow worth repeating
Measure in whatever the scale displays. Convert to the audience’s unit with stone↔kg or lb↔kg tools. Write the compound UK form only for humans who expect it. Store metric in spreadsheets.
Label every number: “72.1 kg (11 st 4 lb).” Dual labels prevent the 11.4 disaster.
Use our stone ↔ kilogram and stone ↔ pound pages when you need exact splits instead of guessing leftover pounds.
Related converters
Frequently asked questions
How many pounds are in a stone?
Exactly 14 avoirdupois pounds. One stone is also exactly 6.35029318 kilograms via the international pound.
Does the US use stone for body weight?
Almost never in everyday US forms or scales. Convert stone to pounds or kilograms when talking to US audiences or software.
Is 12.5 stone the same as 12 st 5 lb?
Not reliably. Decimal stone means fraction of 14 lb (12.5 st = 12 st 7 lb). Spoken “twelve stone five” means 12 st 5 lb. Prefer explicit stone and pounds.