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A weight converter resolves a problem that recurs across kitchens, gyms, pharmacies, shipping docks, and laboratories: how to translate between metric and imperial units without introducing error. Enter a value in kilograms, pounds, grams, ounces, stones, or metric tons, and the converter returns the equivalent in every other unit simultaneously. Whether you are following a recipe written in cups and ounces, tracking body weight in kilograms and pounds, preparing a parcel for international post, or calculating a medication dose, an accurate weight converter eliminates the ambiguity that arises when unit systems collide.
At its core, a weight converter measures the same physical quantity expressed in different units. The metric system — grams, kilograms, and metric tons — is used by most countries and in all scientific contexts. The imperial and US customary systems — ounces, pounds, stones, and tons — remain dominant in the United States and are still used for body weight in the United Kingdom and Ireland.
The converter works by converting the input value to a base unit (usually kilograms), then expressing that value in the target unit. This two-step process ensures that all conversions use a single, consistent reference point. The conversion factors themselves are fixed mathematical constants, defined by international agreement rather than physical measurement. That means a kilogram always converts to the same number of pounds, regardless of location, temperature, or altitude.
The weight converter on Calculator200 supports all major units and displays every equivalent at once, so you can see not just the answer you need but also the broader context of your measurement.
Precision matters. The difference between using 2.2 and 2.20462 as your kilogram-to-pound factor is small for a single conversion, but it compounds over large weights, repeated calculations, or legal and medical contexts where accuracy carries consequences.
The following table lists the exact conversion factors for the most commonly used weight units. These values are defined by the international yard and pound agreement of 1959 and remain the standard for commercial, scientific, and legal purposes worldwide.
| From | To | Multiply by |
|---|---|---|
| Kilogram (kg) | Pound (lb) | 2.2046226218 |
| Pound (lb) | Kilogram (kg) | 0.45359237 |
| Kilogram (kg) | Gram (g) | 1,000 |
| Gram (g) | Ounce (oz) | 0.0352739619 |
| Ounce (oz) | Gram (g) | 28.349523125 |
| Pound (lb) | Ounce (oz) | 16 |
| Stone (st) | Kilogram (kg) | 6.35029318 |
| Metric ton (t) | Kilogram (kg) | 1,000 |
| US short ton | Kilogram (kg) | 907.18474 |
You can perform the most common conversions without a calculator once you know the factors. The process is straightforward multiplication or division.
Multiply the kilogram value by 2.20462. For a 70 kg person, the calculation is 70 × 2.20462 = 154.32 pounds. For a quick estimate, multiply by 2.2. The approximation gives 154 pounds, which is close enough for casual conversation but not for a medical chart or a shipping label.
Multiply the pound value by 0.453592. For 150 pounds, the calculation is 150 × 0.453592 = 68.0389 kilograms. The quick method divides by 2.2, which yields 68.18 kilograms — a difference of about 0.14 kilograms, or roughly 5 ounces.
Multiply the ounce value by 28.3495. For 8 ounces, the calculation is 8 × 28.3495 = 226.796 grams. For cooking, 227 grams is the standard rounded figure.
Multiply the gram value by 0.035274. For 100 grams, the calculation is 100 × 0.035274 = 3.5274 ounces. In a kitchen context, 100 grams is often treated as 3.5 ounces.
If you prefer a tool that handles the arithmetic, the kilogram to pound converter on Calculator200 performs these calculations instantly and displays all unit equivalents in a single view.
Cooking is where weight conversion first becomes practical for most people. A recipe developed in the United States uses cups, ounces, and pounds. A recipe from Europe or Australia uses grams and kilograms. A British recipe might use stones for body weight but grams for ingredients. The result is a kitchen full of competing unit systems, and a scale that may or may not display the unit the recipe calls for.
Weight and volume are not interchangeable in baking. A cup of flour weighs approximately 120 grams in the United States, but a cup of water weighs approximately 237 grams. A cup of honey weighs about 340 grams. This is why professional bakers weigh ingredients rather than scooping them. A weight converter for cooking that handles grams, ounces, and pounds allows you to follow any recipe accurately, regardless of where it was written.
The following table provides common cooking conversions that home bakers and cooks reference frequently.
| Ingredient | 1 cup (US) | 1 ounce | 1 pound |
|---|---|---|---|
| All-purpose flour | 120 g | 28 g | 454 g |
| Granulated sugar | 200 g | 28 g | 454 g |
| Butter | 227 g | 28 g | 454 g |
| Water | 237 g | 28 g | 454 g |
| Honey | 340 g | 28 g | 454 g |
The ounce-to-gram and pound-to-gram figures in the table are consistent across ingredients because they are unit conversions, not ingredient-specific measurements. The cup values vary because a cup measures volume, and different ingredients have different densities.
Body weight is one of the most common personal applications of weight conversion. A person who weighs 70 kilograms may want to know that figure in pounds for a fitness app that uses imperial units. A person who weighs 180 pounds may need to enter their weight in kilograms on a medical form.
The conversion is identical to any other kilogram-to-pound or pound-to-kilogram calculation. What changes is the context. Fitness tracking often uses kilograms, while many gyms in the United States label plates in pounds. A lifter who trains in kilograms and competes in pounds needs to convert back and forth routinely.
For body weight, the quick approximation of dividing by 2.2 or multiplying by 2.2 is usually adequate for casual tracking. For medical records, insurance forms, and clinical settings, the exact factor of 0.45359237 should be used.
Shipping is where weight conversion carries financial consequences. Carriers price shipments by weight, and the unit system varies by country and by mode of transport. Air freight often uses kilograms. Ocean freight uses metric tons or cubic metres. Ground carriers in the United States use pounds.
The critical distinction in shipping is between actual weight, volumetric weight, and chargeable weight. Actual weight is what the scale reads. Volumetric weight is a calculated figure based on the dimensions of the package. Chargeable weight is whichever is greater. Converting between kilograms and pounds is only part of the calculation, but it is an essential part.
A weight converter for shipping that handles kilograms, pounds, and metric tons allows you to verify carrier calculations before you commit to a shipment. If a carrier quotes a price based on 50 kilograms and your own conversion of the same package yields 110.23 pounds, you can confirm that the carrier used the correct factor.
| Unit | Equivalent in kilograms | Common use |
|---|---|---|
| Metric ton (tonne) | 1,000 kg | Ocean freight, bulk materials |
| US short ton | 907.185 kg | US domestic freight |
| UK long ton | 1,016.05 kg | Historical UK shipping |
| Pound | 0.453592 kg | US ground carriers, air courier |
| Ounce | 0.0283495 kg | Small parcels, letters |
In scientific and medical contexts, precision is not optional. A medication dose calculated in milligrams per kilogram of body weight must use the correct kilogram value. A laboratory reagent measured in grams must be converted accurately from ounces if the protocol was written in imperial units.
The metric system is the standard in science and medicine worldwide. The United States is the main exception in everyday life, but even there, scientific and medical practice uses metric units. A patient who reports their weight in pounds will have that figure converted to kilograms for any clinical calculation.
The conversion from pounds to kilograms is performed by multiplying by 0.45359237. A 200-pound patient weighs 90.7185 kilograms. A 50-kilogram patient weighs 110.231 pounds. These conversions are exact to the precision required for clinical work.
Several errors recur frequently enough to deserve explicit mention.
The first is confusing metric tons with US short tons. A metric ton is 1,000 kilograms. A US short ton is 2,000 pounds, which equals approximately 907.185 kilograms. A UK long ton is 2,240 pounds, approximately 1,016.05 kilograms. The difference between a metric ton and a US short ton is nearly 93 kilograms — enough to change a shipping quote significantly.
The second is using the approximation 2.2 in place of the exact factor 2.20462. For small weights, the error is negligible. For a 1,000-kilogram shipment, the approximation yields 2,200 pounds, while the exact conversion yields 2,204.62 pounds — a difference of 4.62 pounds. For a 10,000-kilogram shipment, the difference is 46.2 pounds.
The third is confusing ounces of weight with fluid ounces of volume. An ounce (oz) is a unit of mass. A fluid ounce (fl oz) is a unit of volume. A fluid ounce of water weighs approximately one ounce, but a fluid ounce of oil weighs less, and a fluid ounce of honey weighs more. Weight and volume are not interchangeable.
The following table provides the most commonly needed conversions at a glance. For values not listed, multiply or divide using the factors in the table above.
| Kilograms | Pounds | Stones | Ounces |
|---|---|---|---|
| 1 kg | 2.205 lb | 0.157 st | 35.274 oz |
| 5 kg | 11.023 lb | 0.787 st | 176.37 oz |
| 10 kg | 22.046 lb | 1.575 st | 352.74 oz |
| 25 kg | 55.116 lb | 3.937 st | 881.85 oz |
| 50 kg | 110.231 lb | 7.874 st | 1,763.70 oz |
| 75 kg | 165.347 lb | 11.810 st | 2,645.55 oz |
| 100 kg | 220.462 lb | 15.747 st | 3,527.40 oz |
For values between the listed points, interpolate or use the free weight converter for an exact result.
The exact international conversion factor is 1 kilogram = 2.2046226218 pounds. This value was defined by the international yard and pound agreement in 1959. For everyday use, multiplying by 2.20462 gives a result accurate to four decimal places.
The 2.2 figure is a rounded approximation for quick mental math. The exact factor is 2.20462, which is about 0.2% higher. Over large weights, this difference accumulates and can lead to meaningful errors in shipping, medical dosing, or cooking.
Multiply the number of pounds by 0.45359237. For a quick approximation, divide the pounds by 2.2. For example, 150 lbs is approximately 68 kg. The exact value is 68.0389 kg.
A metric ton (tonne) is exactly 1,000 kilograms. A US short ton is 2,000 pounds, which equals approximately 907.185 kilograms. A UK long ton is 2,240 pounds, approximately 1,016.05 kilograms. Confusing these units is one of the most common weight conversion mistakes.
One avoirdupois ounce is exactly 28.349523125 grams. For cooking and everyday use, 28.35 grams is the standard approximation. One ounce is one-sixteenth of a pound.
Yes. The conversion factors are fixed mathematical constants. You can memorise the key factors (1 kg = 2.20462 lbs, 1 oz = 28.35 g, 1 stone = 6.35029 kg) and perform the calculations manually. Many calculator apps also work offline.
Mass measures the amount of matter in an object and is measured in kilograms. Weight measures the force of gravity on that mass and is measured in newtons. In everyday language, and in most conversion tools, the terms are used interchangeably. The conversion factors apply to mass, which is what people commonly call weight.
Multiply the number of stones by 6.35029. For example, 10 stone is 63.5029 kilograms. One stone equals 14 pounds. Stone is still commonly used for body weight in the United Kingdom and Ireland.
In sum, a weight converter is more than a convenience. It is a precision tool that protects you from the cumulative errors of approximation, the confusion of conflicting unit systems, and the financial and medical consequences of getting the numbers wrong. Whether you are converting kilograms to pounds for a fitness app, grams to ounces for a recipe, metric tons to short tons for a freight quote, or pounds to kilograms for a clinical dose, the weight converter by Calculator200 provides the exact figure and the context you need. Use it with the factors in this guide, and treat every conversion as what it is: a precise translation between two ways of measuring the same physical reality.