Weight

Kilograms, pounds, and stones

Mass (everyday “weight”) is quoted differently depending on country and context. Kitchen scales often switch between grams and ounces; bathroom scales may show kilograms, pounds, or stones and pounds. Shipping labels may mix kilograms with pounds. This converter keeps kilograms, grams, pounds, ounces, and stones in sync so you can translate any one of those readings into the others.

Conversion factors

• 1 kilogram = 1,000 grams
• 1 pound = 0.45359237 kilograms (exact international pound)
• 1 stone = 14 pounds = 6.35029318 kilograms
• 1 pound = 16 ounces

Stones are still common for body weight in the UK and Ireland. The readout that shows whole stones plus remaining pounds mirrors how those scales are usually read aloud.

Worked example

A person of 70 kg weighs about 154.3 lb, which is 11 st 0.3 lb (just over 11 stone). A bag of flour marked 2.5 lb is about 1.134 kg or 1,134 g. A letter of 100 g is about 3.53 oz.

Mass versus weight

In physics, kilograms measure mass while weight is a force. Everyday scales are calibrated so that the kilogram or pound reading matches what people mean by body weight on Earth. This page converts those scale units; it does not compute planetary gravity changes.

Common mistakes

• Treating “stone” as 10 pounds — it is 14.
• Confusing fluid ounces (volume) with ounces of mass.
• Using troy ounces for cooking — troy units are for precious metals, not kitchen weight.

FAQs

Should I use kg or lb for BMI?

Either works if height uses a matching unit. The Body Indexes tool accepts common mass units directly.

Why so many decimal places?

Live sync preserves precision so that converting forth and back stays stable; round when you write a human-facing answer.

Related: Height, Body Indexes, Nutrition.