Convert Between Weight Units

Convert weights between kilograms, pounds, ounces, grams, and more instantly. Essential for scientists, engineers, health professionals, and anyone working with weight measurements. Perform accurate weight conversions across metric and imperial systems.

Our converter supports conversions between metric units (milligrams, grams, kilograms, metric tons) and imperial units (ounces, pounds, stones, tons). Whether you're working on scientific calculations, shipping logistics, health tracking, or cooking recipes, this tool provides precise weight conversions instantly.

Perfect for scientists, engineers, health professionals, logistics managers, developers working with e-commerce applications, or anyone needing quick and accurate weight unit conversions.

Understanding Weight and Mass

Weight and mass are often confused but scientifically different. Mass measures the amount of matter in an object (kilograms), while weight measures the force of gravity on that mass (newtons). In everyday use, we use these terms interchangeably. Our converter handles all common weight units for practical applications.

Metric Weight System:

The metric system uses grams as the base unit. 1 kilogram = 1000 grams, 1 gram = 1000 milligrams. Metric tons (tonnes) equal 1000 kilograms. Used worldwide except in the United States, Liberia, and Myanmar. Scientific measurements always use metric units for consistency.

Imperial Weight System:

The imperial system uses pounds and ounces. 1 pound = 16 ounces, 1 stone = 14 pounds, 1 ton (US) = 2000 pounds, 1 ton (UK) = 2240 pounds. Primarily used in the United States for everyday measurements. Understanding both systems is essential for international commerce.

Weight Conversion in Cooking

Recipe conversions require precise weight measurements. Baking especially needs accuracy - 1 cup of flour weighs 120-130 grams depending on measurement method. Professional bakers use weight (grams) instead of volume (cups) for consistency.

Common Cooking Conversions:

Flour: 1 cup = 120-130g (varies by packing method)
Sugar: 1 cup granulated = 200g, 1 cup brown = 220g
Butter: 1 stick = 113g = 4 ounces = 8 tablespoons
Water: 1 cup = 240ml = 240g (water's density is 1g/ml)

Weight Conversion for Shipping

International shipping requires weight conversion between metric and imperial systems. Postal services use kilograms globally, but US domestic shipping uses pounds. Accurate conversion prevents shipping errors and unexpected costs.

Shipping Weight Tips:

Always round up to avoid underestimating package weight
Include packaging materials in total weight calculation
International shipments use dimensional weight (size × density factor)
USPS uses pounds/ounces, international carriers use kilograms

Body Weight and Health

Medical professionals use kilograms for body weight worldwide, but pounds are common in the US. BMI calculations require weight in kilograms and height in meters. Fitness tracking apps support both systems.

Health Weight Ranges:

BMI Formula: weight (kg) / height (m)²
Healthy BMI: 18.5-24.9 (varies by age and ethnicity)
Weight Loss: Safe rate is 0.5-1 kg (1-2 lbs) per week

Precious Metals and Gemstones

Gold, silver, and gemstones use specialized weight units. Troy ounce (31.1 grams) for precious metals differs from avoirdupois ounce (28.35 grams). Carats measure gemstone weight (1 carat = 200 milligrams).

Precious Metal Conversions:

Troy Ounce: 31.1035 grams (used for gold, silver, platinum)
Carat: 200 milligrams (gemstone weight)
Karat: Purity measure (24k = 100% pure gold)
Pennyweight: 1.555 grams (1/20 troy ounce)

⚖️ Weight Converter