Weight Unit Converter

How to use this tool

1. Enter a value. Type the weight you want to convert into the top input field.
2. Select units. Choose the "from" unit in the left dropdown and the "to" unit in the right dropdown. Units are grouped into Metric, Imperial/US, and Precious/Other.
3. Read the result. The converted value appears instantly in the bottom field, rounded to 6 significant figures.
4. Swap direction. Click the swap button (⇅) to reverse the conversion - the result becomes the new input.
5. Copy the result. Use the Copy button next to the result field to copy the converted value to your clipboard.

kg to lbs and lbs to kg

The kilogram (kg) and the pound (lb) are the two most commonly converted weight units. One kilogram equals approximately 2.20462 pounds; one pound equals approximately 0.453592 kilograms. These factors come from the international pound definition, adopted in 1959: 1 lb = 0.45359237 kg exactly.

Common weight conversions

The metric system: grams and kilograms

The metric system bases weight (more precisely, mass) on the gram. A kilogram is 1,000 grams; a metric ton is 1,000 kilograms. The kilogram is the SI base unit of mass and is defined in terms of the Planck constant since the 2019 redefinition of the International System of Units. For everyday purposes, a kilogram is very close to 2.2 pounds, making the quick mental estimate of "kilos × 2.2 = pounds" accurate to about 0.2%.

Micrograms, grains, and troy pounds

Very small masses can be easier to express in micrograms: 1 microgram (µg, also written mcg) is one-millionth of a gram, and 1,000 micrograms equal 1 milligram. A grain (gr) is a traditional unit still used in some ammunition specifications and historical references; one grain equals exactly 0.06479891 g. The symbol gr means grain, while g means gram, so the two should not be confused.

Troy pounds are uncommon in everyday trade, but are useful when reading older precious-metal references. One troy pound contains 12 troy ounces and equals 373.2417216 g. The converter keeps troy units separate from ordinary avoirdupois pounds and ounces because their sizes and ounce-to-pound relationships differ.

Imperial and US customary weight units

The imperial/US customary system uses ounces (oz), pounds (lb), stone (st), and tons. The relationships are: 16 oz = 1 lb, 14 lb = 1 stone, 2,000 lb = 1 short ton (US), 2,240 lb = 1 long ton (UK). Note that the US short ton and the British long ton are different. The stone is still commonly used for body weight in the UK and Ireland but is not used in the US.

Troy weight: gold, silver, and gemstones

Precious metals such as gold and silver are traded by the troy ounce (31.1035 g), which is heavier than the avoirdupois ounce (28.3495 g). The troy system originates from the medieval trade fair city of Troyes, France, and has been the international standard for bullion pricing for centuries. Spot prices for gold (XAU), silver (XAG), and platinum (XPT) are always quoted in US dollars per troy ounce.

Gemstones are measured in carats (ct), where 1 metric carat = 0.2 g exactly. A 1-carat diamond therefore weighs 200 milligrams. "Carat" as a weight unit should not be confused with "karat" (also written "carat" in UK English), which describes the purity of gold alloys (24-karat gold is pure; 18-karat is 75% gold).

Kitchen and baking context

Weight measurements (grams) are significantly more accurate than volume measurements (cups) for baking. One cup of all-purpose flour can weigh anywhere from 120 to 150 g depending on how it was scooped and packed. Professional pastry chefs universally use gram scales for this reason. If a recipe gives both volume and weight, always use the weight.

Body weight monitoring

Body weight fluctuates 1–3 kg throughout the day due to food, water, and clothing. For meaningful tracking, weigh yourself at the same time each day - ideally in the morning after using the bathroom and before eating. Weekly averages are more informative than day-to-day comparisons.

Scientific mass vs. weight note

In physics, mass (measured in kilograms) is an intrinsic property of matter, while weight is the force exerted on that mass by gravity (measured in Newtons: N = kg × m/s²). A 70 kg person weighs approximately 686 N on Earth and only about 115 N on the Moon (one-sixth the gravity). In everyday language, “weight” and “mass” are used interchangeably, but the distinction matters in science and engineering.