This weight converter tool is the best tool for converting between different weight units. We include not only a real-time weight conversion tool, but also a weight conversion chart (weight conversion table) that allows you to easily convert between units, e.g., lbs to kg, kg to lbs, oz to stones and so on. We will also explain in this article what is weight, discuss if weight is a force or not and even touch briefly on bodyweight, health issues and how to lose weight (and how to gain weight) for those who are interested.
As with other physical quantities, there are several units 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), 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 units' systems used in the world. In the following text, we explain, in more detail, some of the most common units.
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 as mass, 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. If you still wish to know more about the real units of weight, they are the same as force.
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 that an object with a mass of 1kg on the Earth will weigh 9.8 N. But hereafter, we say that this object "weighs" 1kg.
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:
microgram (µg)- 1 millionth of a gram;milligram (mg)- 1 thousandth of a gram;gram (g);kilogram (kg)- 1 thousand grams, but a kilogram is a default unit in the metric system;metric ton (t)- 1000 kilograms;grain (gr)- 1/7000 of a pound;drachm (dr)- 1/16 of an ounce, 1/256 of a pound;ounce (oz)- 1/16 of a pound;pound (lb)- basic weight unit in the US;stone (st)- 14 pounds, often used to quote a person's weight, mostly in the UK and Ireland;US ton, also called a short ton- 2000 pounds; andlong ton, used in the UK- 2240 pounds.
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. For example, there exist similar conversion tables for lengths, like in our length conversion tool.
However, if you're wondering how to convert between grams and cups, this is not the right place - go to our grams to cups calculator. Why isn't it here? Because it's a conversion from weight to volume, which additionally requires the density of the substances.
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.
Kilograms | Ounces | Stones | Pounds |
|---|---|---|---|
10 | 352.74 | 1.5747 | 22.046 |
15 | 529.1 | 2.362 | 33.07 |
20 | 705.5 | 3.1495 | 44.09 |
25 | 881.8 | 3.937 | 55.12 |
30 | 1058.2 | 4.724 | 66.14 |
35 | 1234.6 | 5.512 | 77.16 |
40 | 1411 | 6.299 | 88.18 |
45 | 1587.3 | 7.086 | 99.2 |
50 | 1763.7 | 7.874 | 110.23 |
55 | 1940 | 8.661 | 121.25 |
60 | 2116.4 | 9.448 | 132.28 |
65 | 2293 | 10.236 | 143.3 |
70 | 2469 | 11.023 | 154.32 |
75 | 2645.5 | 11.81 | 165.35 |
80 | 2822 | 12.598 | 176.37 |
85 | 2998 | 13.385 | 187.4 |
90 | 3174.7 | 14.173 | 198.4 |
95 | 3351 | 14.96 | 209.44 |
100 | 3527.4 | 15.747 | 220.46 |
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 conversion 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 three units. If you are interested in converting more than one value, you can repeat the process and even create your own weight conversion chart by writing down all the values for each conversion in a similar fashion to the table above.
Weight conversion between metric units is quite basic, and you can most like 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.
An important remark about the pound is that in the beginning, it was used to measure both force and mass. This shouldn't surprise you if you have read the disclaimer above. When the difference between mass and force was understood, the pound was divided into pound-mass and pound-force depending on what quantity you wanted to measure. As we have explained before, they are both pretty much equivalent as long as we stay on the same planet.
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 (as you will see in a moment) 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 officially 1st = 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. Once people understood the importance of being able to communicate between regions, countries or continents efficiently, the ounce also got a proper definition.
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 and 1 oz = 0.0625 lbs = 0.0283495 kg.
SI units and redefining the kg
We have seen some of the units used for measuring weight. Now let's dive deeper on how the kilogram unit is defined. To begin the story, you need to remember that global trade took over, we measurements needed to be standardized across nations and borders. It just wouldn't do to live in a world where people measured lengths with their own feet and weighed with arbitrary stones. The necessity for a common unit that would always be the same in every corner of the globe was clear.
This is how the scientific quest for the perfect standard began. A perfect scientific standard should not only be the same for everyone everywhere (like following a reference design) but also one that is defined by nature itself, so that we could always refer back to it, even if everything in the world was destroyed.
The first definition of the kilogram was the weight of one liter of water. Which is already better than "the weight of stone" but still has problems. Some of them are due to the fact that the density of water changes with temperature and pressure, making it necessary to set some common values for those magnitudes as well. However, the big problem is that the definition includes other human-made units, meaning that if you lose the definition of a liter (or you get it wrong), the kilogram won't be correctly defined anymore.
Even today the kilogram is still defined based on a piece of metal safely stored in Paris, with copies all over the world. However, this won't last since there are currently two approaches by different scientists to redefine, once and for all, the kilogram. The first approach is to define the kilogram in terms of Planck's constant and Avogadro's number, using an electromagnetic balance and some clever physics.
The second approach (which you can see in the video below) uses the purest, most perfect sphere of Silicon to obtain the amount of Si₁₄ that are contained in precisely one kilogram. We would then have a new definition of a kilogram in terms of the number of Silicon 14 atoms needed to achieve such weight.
It is important to note that this won't change the actual value of a kilogram or how we convert kg to pounds. It would just give us a way to re-create a kilogram (and all other units) even if we lose the reference kilogram, or if we move to a different planet, where the conditions might be very different.
Posts
