Weight Converter
Convert between milligrams, grams, kilograms, tonnes, ounces, pounds and stones.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
1 lb = 0.45359237 kg
About this calculator
Mass conversions follow fixed definitions across the metric and imperial systems. An ounce is 28.349523125 grams and a pound is exactly sixteen of those ounces.
Worked example
calculated with the default values below
Value 1 · From Kilograms (kg) · To Pounds (lb) · Decimal places 4 Result 2.2046 · In grams 1,000.0000 g · In kilograms 1.000000 kg
Method and assumptions
Formula basis and scope
Convert mass via kilograms; US ton and metric tonne are distinct options.
Only the displayed unit definitions are converted; rounding and measurement uncertainty are separate.
Data sources
Disclaimer
These calculators give general conversion results. Rounding and the precision of the value you enter both affect the output, so treat displayed decimals as indicative rather than exact.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
kg = value × F[from]; result = kg ÷ F[to]
- value
- Amount to convert
- from
- Original unit
- to
- Target unit
- F
- Factor in kilograms
F in kg: mg 1e-6, g 0.001, kg 1, tonne 1000, oz 0.028349523125, lb 0.45359237, stone 6.35029318, US ton 907.18474.
Frequently asked questions
Why is a US short ton not the same as a metric tonne?
The converter treats ton as the US short ton of 907.18474 kg, not the metric tonne of 1000 kg, so 1 ton returns about 907 kg. A British long ton would be different again at 1016 kg. Selecting kg or t as the target makes the gap obvious, since t is 1000 kg while ton is roughly 9% less.