Why does 1 kg convert to 2.2046 lb instead of 2.2?

2.2 is a rounded approximation. This converter uses the exact internationally defined factor (1 lb = 0.45359237 kg exactly), described above, which matters when converting large quantities or anything where small errors compound.

Is a UK gallon the same as a US gallon?

No — a UK imperial gallon is about 20% larger than a US gallon, despite sharing the name. Both are listed as separate units here specifically because mixing them up is a common source of volume conversion errors.

Unit Converter

Convert between metric and imperial units of length, weight, volume, area and temperature.

Runs entirely in your browser — nothing you enter is uploaded.

Measure

Value

From

1 metres =

3.28084

feet

Converted via the metre using exact defined factors, not chained approximations.

How to use Unit Converter

Choose a measure — length, weight, volume, area or temperature.
Enter a value and choose the unit you're converting from and to.
Use the Swap button to reverse the direction without re-entering the value.

How this works

Each unit is defined by an exact factor relative to an SI base unit, and conversion goes through that base rather than directly between pairs. This avoids the drift that accumulates when chaining rounded factors. The factors used are the internationally agreed exact definitions: one inch is exactly 25.4 millimetres and one pound is exactly 0.45359237 kilograms, both fixed by the 1959 international yard and pound agreement. Temperature is handled separately because its scales have different zero points and so require an offset, not just a ratio.

value_in_base = value × factor; result = value_in_base ÷ target_factor; °F = °C × 9/5 + 32

Assumptions

US customary units are used for volume. UK imperial pints and gallons are larger and are listed separately.
Weight conversions are mass conversions; they assume standard gravity and do not distinguish mass from force.
Results are rounded for display only — full precision is retained in the calculation.

Worked example

Converting 70 kilograms to pounds.

Value: 70 kg
Factor: 1 lb = 0.45359237 kg exactly
Result: 154.32 lb

70 ÷ 0.45359237 = 154.3236 pounds. Using the common approximation of 2.2 would give 154.0, an error of about a third of a pound — small here, but it compounds badly across repeated conversions or larger quantities.

How to read the result

For anything consequential — shipping weights, medical doses, engineering tolerances — use the full precision figure rather than a rounded one, and be explicit about which system you are in. Most unit confusion incidents come from ambiguous labelling rather than arithmetic: a 'ton' can mean three different masses, and a 'gallon' two different volumes.

Limitations

Fluid volume conversions apply to volume only; converting a volume to a weight requires the substance's density.
US and UK fluid measures share names but differ by about 20% — check which one your source uses.
Does not handle compound or derived units such as miles per gallon or pounds per square inch.

Frequently asked questions

Why does 1 kg convert to 2.2046 lb instead of 2.2?: 2.2 is a rounded approximation. This converter uses the exact internationally defined factor (1 lb = 0.45359237 kg exactly), described above, which matters when converting large quantities or anything where small errors compound.
Is a UK gallon the same as a US gallon?: No — a UK imperial gallon is about 20% larger than a US gallon, despite sharing the name. Both are listed as separate units here specifically because mixing them up is a common source of volume conversion errors.