Weight Converter
Convert weight between kilograms, grams, pounds (lb), ounces (oz), and stone — useful for recipes, fitness, travel, and international shopping.
How to use the calculator
- Enter the value you want to convert.
- Choose which unit you're converting from.
- Choose which unit you want to convert to.
How it's calculated
Worked example: 70 kilograms is 70 ÷ 0.45359237 = 154.3236 pounds, since one pound is defined as exactly 0.45359237 kg. A good mental shortcut is to double and add 10 %: 70 × 2 = 140, plus 14 gives 154 — within a third of a pound of the exact answer. The rule works because 2.2 is very close to the true factor of 2.2046.
1 kg = 1000 g = 2.20462 lb = 35.27392 oz = 0.15747 stone. Pounds and ounces follow the international avoirdupois system (used in the US and UK), and stone is a British unit mostly used for body weight (1 stone = 14 pounds).
Mass and weight are not the same thing
Everyday language treats the words as interchangeable, but in physics they are different quantities. Mass is the amount of matter in an object and is the same everywhere, while weight is the gravitational force acting on that mass and varies with location. A kilogram is a unit of mass; the physical unit of weight is the newton. On the Moon your mass would be unchanged, while your weight would be roughly one sixth.
For practical conversions on Earth the distinction rarely matters, since gravitational acceleration is near enough constant. It does surface in technical contexts: load ratings are quoted in kilograms but calculated in newtons, and a bathroom scale actually measures force and converts to mass on the assumption that you are standing still on Earth.
Frequently asked questions
How many pounds is 1 stone?
1 stone = 14 pounds = about 6.35 kg. Stone is still commonly used to state body weight in the UK and Ireland.
What's the difference between an ounce and a pound?
1 pound (lb) = 16 ounces (oz). Ounces are often used for smaller amounts, like recipe ingredients, while pounds are used for larger weights.
Is this the same "oz" as fluid ounces?
No — this calculator computes weight ounces, not fluid ounces, which measure volume. The two have different conversion factors and shouldn't be confused.