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Weight Converter

Convert mg, grams, kilograms, tonnes, ounces, pounds, stone and US tons.

By CalcHub Editorial · Last reviewed

Quick answer

  • Formula: Result = Value × (factor of from-unit in kg) ÷ (factor of to-unit in kg)
  • Worked example — Converted weight: 0.453592 (full example below).

Weight Converter

Worked example result
Converted weight0.453592
Summary1 lb = 0.453592 kg

One pound is exactly 0.45359237 kg — so a 180 lb person weighs about 81.6 kg.

Diagram: how the Weight Converter works — you enter Weight, From, To; it applies the formula Result = Value × (factor of from-unit in kg) ÷ (factor of to-unit i…; and the worked example gives Converted weight: 0.453592.
How the Weight Converter works — the inputs, the formula, and a worked example (Converted weight: 0.453592).

Convert mass between metric and imperial units through the kilogram. The international pound is defined as exactly 0.45359237 kg, so 1 ounce is exactly 28.349523125 g, 1 stone is exactly 14 lb (6.35029318 kg) and a US short ton is exactly 2000 lb (907.18474 kg).

Note the traps: a US ton (2000 lb) is lighter than a metric tonne (1000 kg ≈ 2204.6 lb), and a British long ton (2240 lb) is different again — this converter uses the US short ton.

The formula

Result = Value × (factor of from-unit in kg) ÷ (factor of to-unit in kg)

Worked example

One pound is exactly 0.45359237 kg — so a 180 lb person weighs about 81.6 kg.

Worked example for the Weight Converter: with Weight 1, From Pounds (lb), To Kilograms (kg), the result is Converted weight: 0.453592; Summary: 1 lb = 0.453592 kg.
The worked example, with the example values entered and the results they give.

The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.

Frequently asked questions

How many pounds are in a stone?

Exactly 14 pounds. Stone is still commonly used for body weight in the UK and Ireland; 10 stone is 140 lb or about 63.5 kg.

Is a ton the same as a tonne?

No. A US short ton is 2000 lb (907.18 kg), a metric tonne is 1000 kg, and a British long ton is 2240 lb (1016 kg).

How many ounces are in a pound?

Exactly 16 avoirdupois ounces. (Troy ounces, used for precious metals, are heavier and divide a troy pound into 12.)

Category: Unit Conversions calculators

Sources & methodology

This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.

Content last reviewed by CalcHub Editorial.

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