Weight Converter
Kilograms, Pounds, Ounces & More

Weight and mass are fundamental measurements used in countless applications, from cooking and shipping to scientific research and healthcare. While "weight" and "mass" are often used interchangeably in everyday language, they have distinct meanings in physics. Mass is the amount of matter in an object (constant everywhere), while weight is the force exerted on that mass by gravity (varies with location).

For practical purposes on Earth, weight and mass are proportional, so weight converters typically work with mass measurements. The distinction becomes important in space or when working with precise scientific measurements, but for most everyday conversions, you can treat them as equivalent.

Common Weight/Mass Units

Metric Units: The kilogram (kg) is the base unit in the metric system. Common metric units include grams (g) for smaller measurements, milligrams (mg) for very small amounts, and metric tons (t) for large weights. The metric system's base-10 structure makes conversions straightforward: 1 kilogram = 1,000 grams = 1,000,000 milligrams.

Imperial Units: The pound (lb) and ounce (oz) are the primary units. Sixteen ounces equal one pound, and 2,000 pounds equal one short ton. The stone (14 pounds) is commonly used in the UK for body weight. Unlike the metric system, imperial weight conversions use the factor of 16, which can make mental calculations more challenging.

When to Use Each Unit

Kilograms and Pounds: Use for body weight, produce at the grocery store, and general weight measurements. Kilograms are standard worldwide, while pounds are common in the United States.

Grams and Ounces: Ideal for cooking ingredients, small packages, and precise measurements. Recipes often specify weights in grams or ounces for accuracy, especially in baking where precision matters.

Metric Tons and Short Tons: Used for large-scale weights like vehicle weights, shipping containers, and industrial materials. One metric ton equals 1,000 kilograms, while one short ton equals 2,000 pounds.

Milligrams and Micrograms: Essential for medication dosages, nutritional supplements, and scientific measurements where extreme precision is required.

Practical Conversion Tips

For quick mental conversions, remember these approximations: 1 kilogram ≈ 2.2 pounds, 1 pound ≈ 0.45 kilograms, and 1 ounce ≈ 28 grams. For precise conversions, use our calculator above, which provides accurate results based on international standards.

When converting between systems, it's often helpful to convert to a common unit first. For example, when converting stones to kilograms, first convert stones to pounds (multiply by 14), then pounds to kilograms (multiply by 0.453592). This two-step process helps avoid errors in complex conversions.

In cooking, weight measurements are more accurate than volume measurements, especially for dry ingredients. A cup of flour can vary significantly in weight depending on how it's packed, but 120 grams of flour is always 120 grams. This is why professional recipes often specify weights rather than volumes.