Conversion tool
Weight & Mass Converter
Convert between metric and imperial weight/mass units. All factors are exact values per NIST SP811 and the International Yard and Pound Agreement.
Formula & conversion factors
1 lb = 0.45359237 kg (exact, by international agreement, 1959)
1 oz = 0.028349523125 kg (exact, 1/16 lb)
1 stone = 6.35029318 kg (exact, 14 lb)
1 short ton (US) = 907.18474 kg (exact, 2,000 lb)
1 long ton (UK) = 1,016.047 kg (exact, 2,240 lb)
1 tonne = 1,000 kg (exact, SI)
General form: value_kg = value_unit × factor_to_kg
1 oz = 0.028349523125 kg (exact, 1/16 lb)
1 stone = 6.35029318 kg (exact, 14 lb)
1 short ton (US) = 907.18474 kg (exact, 2,000 lb)
1 long ton (UK) = 1,016.047 kg (exact, 2,240 lb)
1 tonne = 1,000 kg (exact, SI)
General form: value_kg = value_unit × factor_to_kg
1Worked example: 70 kg in lbs. 70 ÷ 0.45359237 = 154.32 lbs (a common body-weight conversion query).
Reference standard: Base unit: kilogram (kg), the SI base unit of mass.
Imperial–metric factors per International Yard and Pound Agreement (1959) and NIST SP811.
Common questions
How do you convert kg to lbs?
Divide by 0.45359237, or multiply by 2.20462. For a quick estimate: double the kg value and add 10%.
What is the difference between mass and weight?
Mass (measured in kg) is an intrinsic property of matter. Weight is the force of gravity on that mass (measured in newtons). On Earth's surface, they are proportional and used interchangeably in everyday life.
What is a stone?
A stone is an imperial unit equal to 14 pounds (6.35 kg). It is commonly used in the UK and Ireland for body weight.