Weight & Mass Converter

Mass is the amount of matter in an object, and its SI unit is the kilogram (kg). In everyday speech it is called weight, and this converter covers both the metric units (milligrams to tonnes) and the US and imperial ones (ounces, pounds, stones and tons), plus troy ounces, carats and grains.

Strictly, weight is the force that gravity puts on a mass, which is why the newton is here too: under standard gravity, 1 kg weighs 9.80665 N. An object weighs less on the Moon, but its mass is the same.

How to convert mass units

Type a value into any field, and every other unit is calculated at once. By hand, the key factor is 1 lb = 0.45359237 kg, exactly. For example, 70 kg:

1. In pounds: divide by 0.45359237.

   70 / 0.45359237 = 154.32 lb

2. In stones and pounds: a stone is 14 lb, and 154.32 / 14 = 11.02, so 70 kg is 11 stone and about 0.3 lb.

The Pound, Ounce field shows pounds and ounces together, with the ounces after the point: 70 kg is 154.05 in that field, which means 154 lb 5 oz.

Common conversions

Units of mass

• Kilogram (kg): The kilogram is the SI unit of mass in the metric system and is commonly used worldwide.
  Conversion Factor: 1 kg = 1,000 g

• Gram (g): The gram is a metric unit of mass, equal to one-thousandth of a kilogram.
  Conversion Factor: 1 g = 0.001 kg

• Milligram (mg): The milligram is also a metric unit of mass. It is equal to one-thousandth of a gram.
  Conversion Factor: 1 mg = 0.001 g

• Metric Ton (t): The metric ton, also known as a tonne, is a unit of weight used in the metric system. It is equal to 1,000 kilograms.
  Conversion Factor: 1 t (metric) = 1,000 kg

• Short Ton (t): The short ton is a unit of weight used in the United States for non-metric purposes. It is equal to 2,000 pounds.
  Conversion Factor: 1 t (short) = 2,000 lbs

• Long Ton (t): The long ton is a unit of weight used in the United Kingdom and other Commonwealth countries. It is equal to 2,240 pounds.
  Conversion Factor: 1 t (long) = 2,240 lbs

• Quarter (qr): The quarter is a unit of weight used in agricultural contexts in the United States and the United Kingdom. The US quarter is equal to 25 pounds, while the UK quarter is equal to 28 pounds.
  Conversion Factor: 1 qr (US) = 25 lbs; 1 qr (UK) = 28 lbs

• Stone: The stone is a unit of weight primarily used in the United States and the United Kingdom. It is equal to 0.5 quarter. In the US it is equivalent to 12.5 lbs and in the UK it is 14 lbs.
  Conversion Factor: 1 stone (US) = 12.5 lbs; 1 stone (UK) = 14 lbs

• Pound (lbs): The pound is a unit of weight used in the United States and several other countries. It is equal to 16 ounces, or 0.4536 kilogram. To simplify the conversion between kilograms and pounds, it can be stated that 1 kg is equivalent to 2.2 lbs.
  Conversion Factor: 1 lb = 16 oz

• Ounce (oz): The ounce is a unit of weight used in the United States and several other countries. It is equal to 1/16 of a pound.
  Conversion Factor: 1 oz = 1/16 lbs

• Troy ounce (oz t): The troy ounce is a unit of weight primarily used for precious metals. It is equal to approximately 1.09714 ounces, or 31.1034768 grams.
  Conversion Factor: 1 oz t ≈ 1.09714 oz

• Carat (ct): The carat is a unit of weight used to measure the mass of gemstones and pearls. It is equal to 200 milligrams or 0.2 grams.
  Conversion Factor: 1 ct = 0.2 g

• Grain (gr): The grain is a unit of weight commonly used for firearms and ammunition. It is equal to approximately 0.0648 grams, or 1/7000 of a pound.
  Conversion Factor: 1 gr = 0.0648 g

• Newton (N): The newton is a unit of force used in physics and engineering, but it can also be used as a unit of weight under standard gravity. It represents the force required to accelerate a one-kilogram mass at a rate of one meter per second squared.
  Conversion Factor: 1 N = 0.10197 kg, or 1 kg = 9.80665 N

• Metric Quintal (qq): The metric quintal is a unit of mass commonly used in agricultural and trading contexts. It is equal to 100 kilograms.
  Conversion Factor: 1 qq = 100 kg

• Pound, Ounce (lbs.oz): This is a special unit in CalcKit, that combines the pound and ounce units together, separated by a decimal point. For example: 5lbs 3oz can be written as 5.03 lbs.oz, or 3lbs 11oz as 3.11 lbs.oz.