- Enter Weight — Type any numeric value into the input field. The tool accepts positive and decimal numbers for precise measurements.
- Select Units — Choose the source unit (From) and target unit (To) from 11 weight and mass units: microgram, milligram, carat, gram, kilogram, ounce, pound, stone, metric ton, US ton, and imperial ton. Use the swap button to quickly reverse the direction.
- See Results — The conversion happens in real-time as you type. The main result is displayed prominently, and all other unit conversions appear simultaneously below for easy comparison.
- Copy Result — Click 'Copy' to copy the converted value to your clipboard for use in documents, recipes, or calculations.
Weight Converter — Convert Between Mass Units Instantly
The Weight Converter is a free, instant-use tool that converts between 11 weight and mass units, covering the metric system, imperial system, US customary system, and specialty units. Whether you're cooking international recipes, shipping packages, tracking body weight, or working on scientific calculations, this tool provides accurate real-time conversions with an intuitive interface.
All calculations use exact conversion factors established by international standards organizations and are performed entirely in your browser. No data is sent to any server.
Supported Weight Units
- Microgram (μg) — One millionth of a gram. Used in pharmaceutical dosages, medical testing, and analytical chemistry. Many vitamin and mineral measurements use micrograms.
- Milligram (mg) — One thousandth of a gram. Used in medicine, nutrition labels, and pharmaceutical formulations. Common on food packaging worldwide.
- Carat (ct) — Exactly 200 milligrams (0.2 grams). The standard unit for measuring gemstones and diamonds. A 1-carat diamond weighs 200 mg.
- Gram (g) — The base unit of mass in CGS systems. Defined as one thousandth of a kilogram. Used in cooking, nutrition, chemistry, and everyday measurements.
- Kilogram (kg) — The SI base unit of mass. Originally defined by the International Prototype Kilogram, now defined by the Planck constant. The standard unit for most everyday weight measurements globally.
- Ounce (oz) — The avoirdupois ounce equals exactly 28.349523125 grams. Used in the US and UK for food, postal, and everyday measurements. Not to be confused with the troy ounce (31.1 grams) used for precious metals.
- Pound (lb) — 16 ounces or exactly 0.45359237 kilograms. The primary weight unit in the United States for body weight, food, and shipping.
- Stone (st) — 14 pounds or approximately 6.35 kilograms. Used primarily in the UK and Ireland for measuring body weight. One of the few remaining traditional measurement units in British everyday life.
- Metric Ton (t) — 1,000 kilograms. The international standard for large-scale weight measurements including shipping, agriculture, and industrial materials. Also called a "tonne."
- US Ton (Short Ton) — 2,000 pounds or approximately 907.18 kilograms. Used in the United States for large-scale measurements like construction materials and shipping.
- Imperial Ton (Long Ton) — 2,240 pounds or approximately 1,016.05 kilograms. Used historically in the UK and in some shipping contexts. Approximately 1.12 US tons.
Key Conversion Factors
- 1 kg = 2.20462 lb = 35.274 oz
- 1 lb = 16 oz = 453.592 g
- 1 oz = 28.3495 g
- 1 stone = 14 lb = 6.35029 kg
- 1 metric ton = 1,000 kg = 2,204.62 lb
- 1 US ton = 2,000 lb = 907.185 kg
- 1 carat = 200 mg = 0.2 g
Key Features
- Real-Time Conversion — Results update instantly as you type with no delays.
- All-Unit View — See all 10 other unit equivalents simultaneously when you enter a value.
- Swap Button — Quickly reverse conversion direction with one click.
- Smart Formatting — Numbers use locale-aware formatting with thousand separators. Very large or small numbers display in scientific notation.
- Copy to Clipboard — Copy results for use in other applications.
Common Use Cases
- Cooking and Recipes — Convert between grams, ounces, and pounds for international recipes.
- Body Weight — Convert between kilograms, pounds, and stones for health tracking.
- Shipping — Convert package weights between metric and imperial for international shipping.
- Jewelry — Convert between carats, grams, and milligrams for gemstone measurements.
- Medicine — Convert between milligrams, micrograms, and grams for pharmaceutical dosages.
- Science — Convert between all metric units for laboratory measurements.
Privacy and Browser Support
All conversions run entirely in your browser. No data is transmitted to any server. Works in all modern browsers offline.