Weight Converter

Weight Converter

Convert between metric and US customary mass units, including grams, kilograms, metric tons, ounces, pounds, and stones. Enter a value in one unit and the converter returns the equivalents instantly.

Conversion factors

The international avoirdupois pound has been defined as exactly 0.45359237 kg since 1959, which fixes all the customary units below:

• 1 kg = 2.20462 lb (rounded; exactly 1 lb = 0.45359237 kg)
• 1 oz = 28.349523125 g (16 ounces to the pound)
• 1 stone = 14 lb = 6.35029318 kg (commonly used for body weight in the UK and Ireland)
• 1 metric ton (tonne) = 1,000 kg ≈ 2,204.62 lb
• 1 kg = 1,000 g, 1 g = 1,000 mg

To convert pounds to kilograms, multiply by 0.45359237; to convert kilograms to pounds, multiply by 2.20462 (or divide by 0.45359237 for full precision).

Worked example

Convert a body weight of 154 lb to kilograms:

• 154 × 0.45359237 = 69.853..., so 154 lb is about 69.85 kg.

Going the other way, a 25 kg checked-baggage limit in pounds is 25 × 2.20462 = 55.1155, so roughly 55.12 lb. If your bag reads 52 lb at home, you are comfortably under the limit.

When to use this converter

• Air travel: airline baggage allowances are published in kilograms in most of the world, but US home scales usually read in pounds.
• Cooking and baking: recipes from US sources use ounces and pounds, while European recipes weigh ingredients in grams; converting keeps ratios intact.
• Shipping: carriers quote rates per kilogram or per pound depending on the region, so quoting a package weight in the right unit avoids surprises.
• Fitness and health: gym plates, body-weight logs, and medical records mix kilograms, pounds, and (in the UK) stones.

Tips for accurate conversions

• Strictly speaking, kilograms and grams measure mass while pounds are often used loosely for weight. In everyday contexts on Earth the distinction does not change the numbers, but scientific work should use mass units consistently.
• The metric ton (tonne, 1,000 kg) is not the same as the US short ton (2,000 lb, about 907.18 kg) or the UK long ton (2,240 lb, about 1,016.05 kg). Always check which ton a document means.
• Avoirdupois ounces (28.35 g) differ from troy ounces (31.1034768 g), which are used for precious metals. A gold price quoted per ounce means troy ounces.
• Fluid ounces measure volume, not weight. A recipe listing 8 fl oz of milk is asking for about 237 mL, not 227 g.
• Round only at the end. Using 2.2 instead of 2.20462 for kilograms to pounds introduces an error of about 0.2%, which matters for freight billed by weight.

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Other unit tools include the Length Converter, Temperature Converter, Speed Converter, and Pressure Converter. For dates and deadlines, try the Countdown Calculator.