Height & Weight Converter

Conversion Factors

Height and weight conversions between metric and imperial use a small number of constants worth memorising for quick mental conversion. For height: 1 inch = 2.54 cm exactly; 1 foot = 30.48 cm; so a person 5 ft 10 in tall is (5 × 30.48) + (10 × 2.54) = 152.4 + 25.4 = 177.8 cm. Going the other way, divide cm by 2.54 to get inches, then divide by 12 for feet. For quick mental conversion at common heights: 5 ft = 152.4 cm; 5 ft 6 in = 167.6 cm; 5 ft 10 in = 177.8 cm; 6 ft = 182.9 cm; 6 ft 3 in = 190.5 cm. A useful approximation: every 1 cm ≈ 0.4 inch, every 1 inch ≈ 2.5 cm (close enough for everyday use). For weight: 1 pound (lb) = 0.4536 kg; 1 kg = 2.205 lb. The UK uses stones for body weight in everyday speech: 1 stone = 14 lb = 6.35 kg, so 12 stone = 76.2 kg, 15 stone = 95.3 kg, 10 stone = 63.5 kg. Quick mental approximations: 1 stone ≈ 6.3 kg; 1 kg ≈ 2.2 lb; 10 kg ≈ 22 lb ≈ 1 stone 8 lb. A worked example: someone who weighs 80 kg is 80 × 2.205 = 176.4 lb = 12 stone 8 lb (since 12 × 14 = 168, remainder 8.4 lb). A 5 ft 6 in / 65 kg person converts to 167.6 cm / 143.3 lb / 10 stone 3 lb. This calculator handles all four directions cleanly. For BMI calculations, both height and weight must be in metric (height in metres, weight in kilograms) or both in imperial with a different formula — mixing units is the most common BMI mistake.

UK vs US vs Metric

Different countries use different conventions for height and weight, and knowing them matters for everything from medical forms to airline tickets to driving licences. The UK traditionally uses feet and inches for height and stones and pounds for weight in everyday speech, even though the country officially moved to metric in the 1970s. Asking someone their weight in kg gets a blank look from many British people; asking in stones works. Medical and official contexts in the UK increasingly use metric (NHS records, official forms, BMI calculations) but a doctor will happily convert during a conversation. The USA uses feet and inches for height and pounds only for weight (Americans don't use stones at all — saying you weigh '12 stone' confuses an American, who would say '168 pounds'). The US is also the only major country still resisting metric in everyday life. Canada is officially metric but Canadians often quote height in feet/inches and weight in pounds in conversation (a generational thing, with younger people more comfortable in metric). Mainland Europe, Asia, Australia, and most of the rest of the world use centimetres and kilograms exclusively — try saying '5 foot 10' in Germany and you'll get a confused pause. Australia is fully metric and Australians genuinely don't understand stones (one of the few common UK-Australian linguistic gaps). For passport and visa applications, follow the destination country's convention. For online dating profiles, match the platform's regional default (UK app: feet/inches/stones; international app: cm/kg or both). This calculator handles every common conversion so you can convert in either direction quickly.

Travel Medical Form Tips

Filling in medical and travel forms abroad often requires height and weight in unfamiliar units, and getting it wrong can cause real confusion — including being denied entry, refused medication, or causing concern from medical staff. The simple rule: USA wants height in feet/inches and weight in pounds (never metric, never stones). Europe and most of Asia want centimetres and kilograms. Australia and New Zealand use metric. The UK's increasing medicalisation of metric means UK travel insurance and medical questionnaires often want kg now, even though the asker knows their weight in stones. Practical preparation: know your measurements in both systems before travelling. Memorise your height in cm and feet/inches, and your weight in kg, stones/lb, and lb only — it takes 30 seconds with a calculator and saves repeated headaches on arrival. For US travel: write down your height as a single decimal in inches (e.g. '70 inches' for 5 ft 10) since some forms have a single inches field. For US-prescribed medication dosing (which often uses pounds and is sometimes calculated as 'X mg per pound of body weight'), state your weight in pounds. Keep medical records with metric measurements when seeking treatment abroad — most international hospitals and pharmacies will convert, but giving them the right units upfront speeds care. Children's medication dosing in particular is by kg (most international guidance) or by pounds (some US prescribing), and the conversion error has real safety implications, so always verify which the prescribing healthcare provider is using. Airlines mostly use metric for baggage, but US carriers display in pounds — same allowance, different labelling. This calculator gives you all your measurements in a single check so you can quote the right units in any country.

When to Seek Medical Advice

Calculator results are estimates based on population averages and statistical formulas — they are not medical diagnoses. Consult your GP if calculator results suggest a health concern, if you have symptoms requiring attention, or if you are managing a chronic condition where precise monitoring is important. Regular health checks (annual GP review, NHS Health Check for those aged 40-74) provide professional assessment using validated clinical tools. Use health calculators to inform conversations