Weight Converter

How the Weight Converter Works

A weight converter (more precisely a mass converter) changes a measurement from one unit into another using fixed conversion factors. The kilogram is the SI base unit of mass, so the tool converts your value to kilograms internally and then to the unit you choose, guaranteeing consistent and accurate results.

Within the metric system the relationships are powers of ten: 1 kilogram = 1,000 grams, 1 gram = 1,000 milligrams, and 1 tonne (metric ton) = 1,000 kilograms. The link to imperial and US customary units is defined exactly through the pound: 1 pound = 453.59237 grams, which equals 0.45359237 kg. From this single exact figure every other imperial conversion follows.

That definition means 1 kilogram = 2.20462 pounds (often rounded to 2.2046 lb), 1 pound = 16 ounces, and 1 stone = 14 pounds = 6.35029 kg. To convert manually, multiply by the linking factor; to reverse the conversion, divide by it.

Common Weight Conversion Factors

Use this quick-reference table for the conversions people look up most. It covers everyday cooking, body weight, postage and bulk goods.

From	To	Multiply by
1 kilogram	pounds	2.20462
1 pound	grams	453.592
1 pound	kilograms	0.453592
1 ounce	grams	28.3495
1 stone	kilograms	6.35029
1 tonne	kilograms	1000
1 gram	ounces	0.035274

For example, to convert 70 kg to pounds, multiply 70 by 2.20462 to get about 154.32 lb. To convert 8 ounces to grams, multiply 8 by 28.3495 to get 226.8 g, the classic half-pound used in recipes.

When You Need to Convert Weight

Switching between metric and imperial mass units is a daily task in many situations:

• Cooking and baking, where recipes mix grams, ounces and pounds and precision matters for results.
• Body weight, given in kilograms in most countries, in pounds in the US, and in stones and pounds in the UK (so 80 kg is about 12 st 8 lb).
• Shipping and postage, where parcel rates depend on grams or pounds.
• Fitness and nutrition, converting food labels and dumbbell weights.
• Industry and freight, where bulk loads are measured in tonnes or short/long tons.

Note that a metric tonne (1,000 kg) differs from the US short ton (2,000 lb, about 907 kg) and the UK long ton (2,240 lb, about 1,016 kg), so always confirm which ton is meant. Because the pound is defined exactly in grams, all the conversions here are precise.

Tips for Accurate Weight Conversion

The calculator handles the arithmetic, but a few habits help you avoid errors and interpret results correctly, particularly in cooking and health contexts where small differences add up.

• Mass versus weight. In everyday language we say weight, but kilograms and pounds technically measure mass. For all practical earth-bound purposes the distinction does not change the numbers, so you can convert freely.
• Round only at the end. Carry full precision through intermediate steps and round the final answer. For instance, converting 150 lb gives 68.0389 kg, which you might present as 68 kg.
• Stones and pounds together. UK body weight is often two numbers, such as 12 st 6 lb. Convert the stones (x6.35029) and the pounds (x0.453592) separately, then add: 12 st 6 lb is about 78.93 kg.
• Know your ton. A recipe or shipping quote may use a metric tonne, a US short ton, or a UK long ton, each a different size. Confirm before converting.

For mental estimates, a kilogram is a bit over two pounds (multiply kg by 2.2), an ounce is roughly 28 grams, and a stone is about 6.35 kg. These shortcuts are quick for the grocery store or gym, while the exact factors above give the precision needed for nutrition labels, postage and lab work. Keep this weight converter handy so you always apply the right factor in the right direction.