Weight Calculator

Mass is the amount of matter in an object and doesn't change regardless of location. Weight is the force exerted by gravity on that mass and varies depending on gravitational strength. On the moon, your mass stays the same, but your weight would be about 1/6 of what it is on Earth.

The United States inherited the British Imperial system and has maintained it through tradition and infrastructure. While the metric system was made legal in the US in 1866, the country never fully converted due to the high cost of changing existing systems, signage, and equipment. Most other countries adopted the metric system for its simplicity and universal standardization.

This calculator uses scientifically accurate conversion factors defined by international standards. The conversions are precise to several decimal places, making them suitable for both everyday use and scientific applications. For legal and commercial purposes, always verify with local standards.

A stone is a unit of weight primarily used in the United Kingdom and Ireland for measuring human body weight. One stone equals 14 pounds or approximately 6.35 kilograms. It's rarely used outside of these regions and for non-body-weight measurements.

Carats are primarily used to measure the weight of gemstones and pearls. One carat equals 200 milligrams or 0.2 grams. The term comes from the carob seed, which ancient merchants used as a reference weight because the seeds were thought to have a uniform weight. Don't confuse this with "karat," which measures the purity of gold.

One pound equals exactly 453.59237 grams. This is the internationally agreed-upon definition. For quick mental calculations, you can round it to 454 grams. Conversely, one kilogram (1000 grams) equals approximately 2.20462 pounds.