Weight and Mass Converter – Convert Between All Weight Units

Weight and Mass Converter

Convert between 100+ weight and mass units including kilograms, grams, pounds, ounces, and more.

Weight and Mass Conversion Calculator

Converting…

Conversion Result

Converted Value
0
Conversion Formula
1 kg = 1 kg

Conversion Steps

Unit Details

Kilogram
Symbol:
kg
Conversion Factor:
1 kilogram
The kilogram is the base unit of mass in the International System of Units (SI). It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015 × 10^-34 when expressed in the unit J⋅s, which is equal to kg⋅m²⋅s^-1.
Pound
Symbol:
lbs
Conversion Factor:
0.45359237 kilograms
The pound is a unit of mass used in the imperial and United States customary systems of measurement. The international avoirdupois pound is defined as exactly 0.45359237 kilograms.

About Weight and Mass Conversion

Understanding Weight vs. Mass

While often used interchangeably in everyday language, weight and mass are distinct physical concepts. Mass is a measure of the amount of matter in an object, while weight is the force exerted on that object by gravity. In scientific contexts, mass is measured in kilograms, while weight is measured in newtons. However, in everyday usage, weight is commonly expressed in mass units like pounds or kilograms, assuming standard gravity.

History of Weight Measurement

Weight measurement has ancient origins, with early civilizations using natural objects as reference standards. The Egyptians used weights called “deben,” while the Romans had their “libra” (pound). The metric system, developed during the French Revolution, introduced the kilogram as the base unit of mass, originally defined as the mass of one liter of water at 4°C. Today, the kilogram is defined by the Planck constant, ensuring greater precision and stability.

Common Weight and Mass Units

Weight and mass units can be categorized into several systems:

  • Metric System: Based on the kilogram (kg), with prefixes like kilo- (1000), centi- (0.01), and milli- (0.001) for multiples and fractions.
  • Imperial System: Used primarily in the United States, includes ounces, pounds, stones, and tons.
  • Troy System: Used for precious metals, with troy ounces and troy pounds.
  • Apothecary System: Historically used in pharmacy, with grains, scruples, and drams.
  • Scientific Units: Used in physics and chemistry, such as atomic mass units and daltons.

Practical Applications of Weight Conversion

Weight conversion is essential in numerous fields and everyday situations:

  • Cooking and Baking: Converting between metric and imperial measurements for recipes.
  • Shipping and Logistics: Calculating shipping costs based on weight in different units.
  • Healthcare: Measuring medication dosages and patient weight.
  • Science and Engineering: Converting between units for calculations and experiments.
  • International Trade: Converting weights for products traded between countries with different measurement systems.

How to Use This Converter

Our weight and mass converter tool allows you to convert between over 100 different units quickly and accurately. Simply enter the value you want to convert, select the original unit, choose the target unit, and click the Convert button. The tool will display the converted value, the conversion formula used, and step-by-step calculations showing how the conversion was performed.

This converter is particularly useful for students, professionals in healthcare and engineering, chefs, international traders, and anyone who needs to work with different weight and mass units. All conversions are based on the latest international standards to ensure accuracy.

Frequently Asked Questions

What is the difference between weight and mass?
Mass is the amount of matter in an object and remains constant regardless of location. Weight is the force exerted on that mass by gravity and varies depending on the gravitational field. For example, an object has the same mass on Earth and the Moon, but it weighs less on the Moon due to lower gravity. In everyday usage, the terms are often used interchangeably.
How many pounds are in a kilogram?
There are approximately 2.20462 pounds in a kilogram. More precisely, 1 kilogram equals 2.20462262185 pounds. This conversion is based on the international agreement that defines 1 pound as exactly 0.45359237 kilograms.
What is a troy ounce and how does it differ from a regular ounce?
A troy ounce is a unit of weight used for precious metals and gemstones, equal to 31.1034768 grams. A regular (avoirdupois) ounce is used for most other purposes and equals 28.349523125 grams. The troy ounce is about 10% heavier than the regular ounce. There are 12 troy ounces in a troy pound, compared to 16 regular ounces in an avoirdupois pound.
How do I convert grams to ounces?
To convert grams to ounces, divide the number of grams by 28.349523125. For example, 100 grams equals 100 ÷ 28.349523125 = 3.527 ounces. This is because 1 ounce is defined as exactly 28.349523125 grams.
What is an atomic mass unit (amu)?
An atomic mass unit (amu), also called a dalton (Da), is a unit of mass used to express atomic and molecular weights. It is defined as one-twelfth the mass of a carbon-12 atom, approximately 1.66053906660 × 10^-27 kilograms. This unit is essential in chemistry and physics for measuring the mass of atoms, molecules, and subatomic particles.
How many kilograms are in a ton?
There are 1,000 kilograms in a metric ton (tonne). However, there are different types of tons: a short ton (US) equals 907.18474 kilograms, and a long ton (UK) equals 1,016.0469088 kilograms. When converting, it’s important to specify which type of ton you’re referring to.
What is a carat and how is it used?
A carat is a unit of mass equal to 200 milligrams or 0.2 grams. It is primarily used for measuring gemstones and pearls. The term comes from the carob seed, which was historically used as a weight standard due to its consistent size. One carat is divided into 100 points, allowing for precise measurements of small gemstones.
How do I convert stones to kilograms?
To convert stones to kilograms, multiply the number of stones by 6.35029318. For example, 10 stones equals 10 × 6.35029318 = 63.5029318 kilograms. A stone is a British unit of weight equal to 14 pounds, primarily used for measuring human body weight in the UK and Ireland.
What is the Planck mass?
The Planck mass is a fundamental unit of mass in the system of natural units known as Planck units. It is approximately 2.17651 × 10^-8 kilograms. It is derived from fundamental constants of nature: the speed of light, the gravitational constant, and the reduced Planck constant. The Planck mass represents the scale at which quantum gravitational effects are believed to become significant.
Why are there so many different units for measuring weight and mass?
The variety of weight and mass units developed from different historical, cultural, and practical needs. For example, the troy system evolved for precious metals, the apothecary system for medicine, and different regions developed their own units for trade. While the metric system has standardized many measurements, traditional units remain in use in specific contexts and regions, leading to the need for conversion tools.

Weight and Mass Converter Tool

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This tool is for educational purposes. Always double-check your conversions for critical applications.