Weight Converter - Convert Between Kilograms, Pounds, Ounces, Stones, Grams and More

This weight converter tool is the best tool for converting between different weight units. We include not only a real-time weight converter tool but also a weight conversion chart that allows you to easily convert between units, e.g., lbs to kg, kg to lbs, oz to stones, and so on.

As with other physical quantities, there are several unit systems to measure weight (mass). The most popular and widespread of them is the International System (SI) and its units like kilogram (kg), gram (g), and decagram (dag). Another primary system of units is the Imperial System, with units such as the pound (lbs) and the ounce (oz). However, these are not the only unit systems used in the world.

What is Weight?

Before we begin talking about weight units and how to convert between them, we need to issue a HUGE DISCLAIMER. The real (technical) definition of weight is very different from what we understand in our everyday life. Technically speaking, weight is a force, in particular, the force exerted by the Earth (or another planet) on an object. Therefore, it cannot be measured in kilograms, pounds, or tons, but only in Newtons and equivalent units.

What we usually call "weight" in our everyday life is technically referred to asmass, and it measures the amount of matter in an object. The gravitational force that the Earth exerts on us is approximately constant. Thus, we can utilize mass and weight almost interchangeably by just multiplying or dividing it by the gravitational acceleration, g, of the Earth.

To avoid confusion or unnecessary complications, we will talk about mass units but refer to them as weight units. We adopt the common way of speaking instead of the technical one. For those who would like to be more technical and precise, we remind you that an object with a mass of 1 kg on the Earth will weigh 9.8 N. But hereafter, we say that this object "weighs" 1 kg.

Convert from Pound to kg, Convert from kg to lbs...

When it comes to converting from one weight unit to another by hand, it can be easy (e.g., to switch from kilograms to grams, you just multiply kilograms by 1000) or not so easy (like switching from lbs to kg or kg to lbs), but using a weight converter like this, everything becomes easy as pie.

With this weight converter, you can easily and effortlessly convert kg to pounds (and re-convert pounds to kg), grams to stones, or any other two units you desire. We offer the full list of available units below:

To get your head around the conversions between these units, feel free to use the weight conversion chart in the next section. Conversion charts and conversion tables are very helpful. They visually show you the equivalence between different units of any magnitude, not only weight.

Weight Conversion Chart

To quickly find values expressed in multiple units you can use our weight conversion chart (weight conversion table). Below, we attach probably the most standard weight conversion chart available, which compares kilograms, ounces, pounds, and stones, making it easy to convert from kg to lbs, from kg to ounces and so on.

We remind you that weight conversion charts can include any number of units based on your needs and preferences. The weight conversion table shown above is just one example that includes 4 of the most common units and a range of values that are frequently used.

How to Build a Weight Conversion Table?

The table above includes only 4 out of the 15+ units we have available in this weight converter tool. To build your own, choose the desired units from the drop-down menus and type in the desired values. Our calculator will return results in real-time for each of the other units.

Weight conversion between metric units is quite basic, and you can most likely do it without any table - e.g., 1 kilogram = 1000 grams or 1 ton equals 1000 kilograms. Things get a bit more complicated when using the imperial system. Here, for example, 1 stone = 14 pounds which equals 224 ounces. Conversion between systems is even more complicated! This conversion calculator then becomes very helpful, as, e.g., 1 kilogram = 35.274 ounces, 0.15757 stones, and 2.2046 pounds.

Pound (lb)

The pound is probably the most used imperial unit for measuring weight, especially in countries that have adopted the International System, such as the US, UK, and Canada. The pound has its origin in the Roman unit of weight called libra. Hence, the abbreviation is lb. From there, it evolved into the British pound (with various definitions and values), eventually becoming what we now know as the pound.

Nowadays, the value of the pound doesn't vary from place to place. It has been legally regulated to a fixed value for everyone, everywhere. Since in science, SI-units are used, and since a lot of effort has been put into perfectly defining the kilogram, it is natural to define the pound in relation to the kilogram. The pound is legally defined in terms of the conversion lbs to kg as 1 lb = 0.45359237 kilograms which leads to conversion from kg to lbs being 1kg = 2.20462 lbs.

Stone (st)

It is easy to understand where the name stone comes from. It dates back to the times when people measured the weight of objects by putting a similar weight of stones on the other side of a Roman-style balance. With the evolution of measuring techniques, the unit got standardized to what is now the stone, meaning that its value does not depend on the size of the stone you chose anymore.

The stone is used mostly in the British Isles and Ireland, most commonly to measure people's weight rather than as an everyday unit. You might weigh 20 st because you ate too much for too long but, ironically, you would measure the weight of your food in pounds. The definition of stone is officially1st = 14 pounds = 6.35029318 kg.

Ounce (oz)

The last unit we will explain in detail is the ounce. We have left it until last because it is the final piece of the Imperial System units "puzzle". Just like the stone and the pound, the ounce has a historical and customary origin, which means that for many years people used the ounce unit with no standardized value across all regions until fairly recently.

The definition of the ounce, however, is much easier to do within the Imperial System, since the ounce is defined as 1/16 lb. From there, you can convert from lbs to kg to obtain the SI value of an ounce. It is possible to do it the other way around to get ounces from kilograms. You need to convert from kg to lbs and then to ounces. The equivalences are as follows:1 lbs = 16 oz = 0.45359237 kg and1 oz = 0.0625 lbs = 0.0283495 kg.

Is Weight a Force? Are Mass and Weight the Same Thing?

We have mentioned before that mass and weight are not the same, but we can treat them as the same quantity as long as we stay on the Earth. The reason we can talk about weight and mass in our daily life is that they are both proportional to each other. Let's demonstrate that with Newton's second law. This law states that the force and mass are proportional to the accelerationof any object. F = m × a where Fis the force (for us, it is the weight), m is the mass of the object, and a is the acceleration, which for a falling object isg or the gravitational acceleration.

The important part is that for all objects on the Earth, the acceleration downwards will always be the same, approximatelyg = 9.8 m/s². This means that the weight Fand the mass m are still not the same thing, but they are exactly proportional so you can convert weight to mass and vice versa.