Is a pound exactly 0.45359237 kg?

Yes, by definition since 1959. The avoirdupois pound is defined in terms of the kilogram, so pound-to-kilogram conversions are exact and any imprecision is in the rounding, not the factor.

What is the difference between a US ton and a metric tonne?

A US short ton is 2,000 lb, about 907.18 kg. A metric tonne is 1,000 kg, and a UK long ton is 2,240 lb, about 1,016 kg. Three different things share the word, which is why freight quotes state which one they mean.

Conversionsmeasurement

Weight and Mass Converter

Mass between metric and imperial, including the two different tons. A short ton and a long ton differ by about 10%, which is not a rounding difference.

Also called: kg to pounds, lbs to kg, mass converter.

Result

2.204623

1 Kilogram is 2.204623 Pound. The factor is 2.2046226218, and the inverse is 0.45359237. The table below gives the same value in every weight unit at once.

Conversion factor

2.2046226218

Inverse factor

0.45359237

Value in kg

Converting from

Kilogram

Converting to

Pound

Dimension

weight

How this is calculated

The same value in every weight unit

Unit	Value
Milligram	1,000,000
Gram	1,000
Kilogram	1
Tonne (metric)	0
Ounce	35.27
Pound	2.2
Stone	0.16
Short ton (US)	0

Method and background

How this is calculated

A pound is exactly 0.45359237 kilograms by definition. The tons are where care is needed: the US short ton is 2,000 lb, the imperial long ton is 2,240 lb, and the metric tonne is 1,000 kg. All three are called "ton" in ordinary speech.

result = value * factor_from / factor_to

k: Each unit's size in kg

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

1 kg in pounds

Value: 1
From: Kilogram
To: Pound

Result2.204623

1/0.45359237, exact by definition

Open this example

a short ton is not a tonne

Value: 1
From: Short ton (US)
To: Tonne (metric)

Result0.907185

2000 lb x 0.45359237 kg

Open this example

identity

Value: 7
From: Kilogram
To: Kilogram

Result7

degenerate case

Open this example

Frequently asked questions

Is a pound exactly 0.45359237 kg?: Yes, by definition since 1959. The avoirdupois pound is defined in terms of the kilogram, so pound-to-kilogram conversions are exact and any imprecision is in the rounding, not the factor.
What is the difference between a US ton and a metric tonne?: A US short ton is 2,000 lb, about 907.18 kg. A metric tonne is 1,000 kg, and a UK long ton is 2,240 lb, about 1,016 kg. Three different things share the word, which is why freight quotes state which one they mean.