Skip to main content

Weight and Mass Converter

Popular Weight and Mass unit conversions

Weight & Mass Converter — Convert Any Unit of Weight Instantly

Our free online Weight & Mass Converter lets you instantly convert between 60+ units of weight and mass — from everyday units like kilograms and pounds to scientific units like atomic mass units and Planck mass. Whether you need to convert kilograms to pounds, grams to ounces, metric tons to short tons, or even grains to carats, this tool delivers fast and highly accurate results with no installation required.

Weight and mass are closely related but distinct physical concepts. Mass is the amount of matter in an object; weight is the force gravity exerts on that mass. In everyday use, the terms are used interchangeably. Units span multiple systems:

  • Metric (SI): kilogram (kg), gram (g), milligram (mg), microgram (µg), tonne (metric ton)
  • Imperial / US customary: pound (lb), ounce (oz), stone, hundredweight, short ton, long ton
  • Troy & apothecary: troy pound, troy ounce, pennyweight, grain, scruple, carat
  • Scientific: atomic mass unit (u), Planck mass, electron mass, proton mass
  • Historical / Biblical: talent, mina, shekel, drachma, denarius

All conversions use internationally standardized factors and high-precision arithmetic, making this tool reliable for science, cooking, shipping, fitness, and everyday tasks.

Common Weight & Mass Conversion Reference

Here are the most frequently used weight and mass conversions for quick reference:

  • 1 kilogram = 1000 grams = 2.20462 pounds = 35.274 ounces
  • 1 pound = 0.453592 kilograms = 453.592 grams = 16 ounces
  • 1 ounce = 28.3495 grams = 0.0625 pounds
  • 1 metric ton (tonne) = 1000 kilograms = 2204.62 pounds = 1.10231 short tons
  • 1 short ton (US) = 907.185 kilograms = 2000 pounds
  • 1 long ton (UK) = 1016.05 kilograms = 2240 pounds
  • 1 stone (UK) = 6.35029 kilograms = 14 pounds
  • 1 carat = 0.2 grams = 200 milligrams

Frequently Asked Questions — Weight & Mass Converter

Question: How do I use the Weight and Mass Converter?

Answer: Select the unit you are converting from in the left list and the unit you are converting to in the right list, then type a value in the input box. The result appears instantly across all listed units simultaneously.

Question: How many grams are in a pound?

Answer: There are exactly 453.59237 grams in one pound (avoirdupois). This is the internationally standardized definition used in trade and everyday measurements.

Question: What is the difference between weight and mass?

Answer: Mass is the amount of matter in an object and remains constant regardless of location. Weight is the gravitational force acting on that mass and varies by location (e.g., on the Moon you weigh less but your mass is unchanged). In everyday use the terms are interchangeable, but in physics they are distinct.

Question: How many kilograms are in a metric ton?

Answer: One metric ton (also called a tonne) equals exactly 1,000 kilograms or approximately 2,204.62 pounds. It is different from a US short ton (907.185 kg) and a UK long ton (1,016.05 kg).

Question: How do I convert kilograms to pounds?

Answer: Multiply the number of kilograms by 2.20462 to get pounds. For example, 70 kg × 2.20462 = 154.324 lbs. You can also use the converter above for instant, precise results.

Question: What is a carat in weight?

Answer: In gemology, 1 carat (ct) equals exactly 0.2 grams or 200 milligrams. Carats are used to measure the weight of diamonds and other precious gems. Note that this is different from the karat (kt) used to measure the purity of gold.

Question: How many ounces are in a pound?

Answer: There are exactly 16 ounces (avoirdupois) in one pound. This is the standard for everyday goods and commodities. Troy weight (used for precious metals) has 12 troy ounces per troy pound.

Question: What is a stone in weight?

Answer: A stone is a unit of weight used primarily in the UK and Ireland, equal to 14 pounds or approximately 6.35029 kilograms. Body weight is commonly expressed in stones and pounds in the UK.

Question: How accurate are the weight conversions in this tool?

Answer: All conversions use internationally standardized conversion factors with up to 12 significant digits of precision, making results suitable for science, engineering, commerce, and everyday use.

Question: Can I convert between metric and imperial units of weight?

Answer: Yes. The converter supports full cross-system conversion between metric units (kilogram, gram, milligram, tonne, etc.) and imperial/US customary units (pound, ounce, stone, short ton, long ton), as well as troy, apothecary, and scientific units.