Definition

Weight (more precisely, mass in everyday contexts) measures how much matter is in an object. Common units include kilograms (kg), grams (g), pounds (lb), ounces (oz), and stone (st). This tool converts between metric and imperial systems using standard factors accepted by NIST and international standards bodies.

Origin and History

Metric units originate from the late 18th‑century French metrication, later formalized as SI (International System of Units). Imperial and US customary weight units such as pounds and ounces trace back to Roman libra and medieval trade practices. The stone remains commonly used in the UK for body weight. Modern science and global trade predominantly use metric units for consistency.

Current Use

• Cooking and baking: convert between grams/ounces for recipes and nutrition labels.
• Fitness and health: kg ⇄ lb or st ⇄ lb for body weight and gym plates.
• Shipping and logistics: grams/kilograms ⇄ pounds/ounces for parcel labels.
• Science and engineering: precise conversions for laboratory and manufacturing inputs.

Examples

• Example 1: 2.5 kg to lb → 2.5 × 2.20462 = 5.51155 lb (≈ 5.512 lb)
• Example 2: 12 oz to g → 12 × 28.349523125 = 340.194 g
• Example 3: 150 lb to kg → 150 × 0.45359237 = 68.0389 kg
• Example 4: 9 st to lb → 9 × 14 = 126 lb

Popular Weight Conversions

• Kilograms to Pounds: 1 kg = 2.20462 lb
• Pounds to Kilograms: 1 lb = 0.453592 kg
• Ounces to Grams: 1 oz = 28.3495 g
• Grams to Ounces: 1 g = 0.035274 oz
• Stone to Pounds: 1 st = 14 lb