⚖️ Weight Converter
Convert kg, g, lb, oz, stone. Runs privately in your browser.
Everything anchored to the kilogram
The kilogram is the SI base unit, so everything anchors to it: 1 g = 0.001 kg, 1 lb = 0.45359237 kg exactly (since the 1959 international yard-and-pound agreement), 1 oz = 1/16 lb, 1 stone = 14 lb = 6.35029318 kg. The converter routes your value through kilograms to the target unit.
Stones trip up cross-Atlantic readers: a UK person '11 stone 4' is 158 lb, a figure no single decimal shows cleanly. Convert to pounds for granular targets, to kilograms for medical forms.Body-weight contexts have their own conventions worth knowing. Medical dosing is always kilograms — never convert a weight-based drug dose from pounds without a clinician. Boxing, weightlifting and horse racing use pounds or stone by tradition, and aviation fuel and cargo use metric tonnes. When in doubt about which unit a form wants, enter kilograms: it is the only one of these units defined directly by the SI.
The factors, and why they are exact
target = value × (factor_from ÷ factor_to) with kg as the base: g 0.001, lb 0.45359237, oz 0.028349523125, st 6.35029318.
Ounces, fluid ounces and troy weight
- Mixing up ounces (mass) and fluid ounces (volume) — 1 fl oz of water ≈ 1.04 oz, but only for water.
- Using troy ounces (31.1 g) for precious metals in a standard-ounce field.
- Assuming 1 kg = 2 lb. It's 2.20462 lb — the 2:1 shortcut loses 10%.
- Ignoring that 'stone' is rarely used outside the UK and Ireland — international forms want kg.Shipping weights quoted in 'kg' that actually mean kilograms-force or chargeable volumetric weight — freight quotes use dimensional weight, not scale weight.
Pounds, kilos and stone
A 180 lb person: 180 × 0.45359237 = 81.65 kg. A 75 kg athlete: 165.35 lb, or 11 stone 11 lb (165.35 ÷ 14 = 11.81 stone). A 500 g flour pack is 1.102 lb — nearly half a pound more than the 'about 450 g' some recipes assume.
Weight questions
How many pounds in a kilogram?
Exactly 2.2046226218 — the pound is defined as 0.45359237 kg, so the ratio is exact.
What is a stone in kg?
14 lb = 6.35029318 kg. An 11-stone person weighs about 69.85 kg.
Is this converter metric-tonne aware?
It covers g/kg/lb/oz/st. 1 metric tonne = 1000 kg — type it in kilograms.
Why do food labels use both kJ and kcal, grams and ounces?
Label laws differ by country; the mass units here (g, oz) are the same ones the labels use.
Does it handle carats?
No — carats (0.2 g) are gem trade units outside the everyday set.
How heavy is 200 grams in ounces?
200 × 0.001 ÷ 0.028349523125 ≈ 7.05 oz — a common kitchen conversion.
What is 10 stone in kg?
10 × 6.35029318 = 63.5 kg — enter 10 st and read kg.
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Tip: double-check inputs before relying on results for important decisions.