Weight Converter

The weight converter switches a value between 20 weight and mass units: Carat, Grain, Gram, Hundredweight, Kilogram, Long Hundredweight, Long Ton, Metric Ton, Microgram, Milligram, Mole, Ounce, Pennyweight, Pound, Short Hundredweight, Short Ton, Stone, Ton, Troy Ounce, and Troy Pound, covering everyday units alongside specialized troy and mole-based measurements.

• Values accept whole numbers (42), decimals (3.14), fractions (3/4), mixed numbers (5 1/16 or 1-3/8), and scientific notation (1.5e3); dollar signs, commas, and percentage symbols are stripped automatically.
• The result multiplies the input by the source unit's factor divided by the target unit's factor, with an optional step-by-step view that shows that ratio and the substituted arithmetic.
• A swap control reverses the source and target units without re-selecting either one, useful for checking a conversion in both directions.
• Converting to or from moles requires a molecular weight, in grams per mole; the default is 18.015 g/mol, the molecular weight of water, and should be changed to match the substance actually being measured.
• Settings holds the display precision, from 2 to 10 decimal places, applied to whichever pair of units is selected.

Water's molecular weight is 18.015 grams per mole, so 2 moles of water weighs 36.03 grams: 2 x 18.015 = 36.03. The same mole formula works for any substance once its molecular weight is entered; table salt (sodium chloride), at 58.44 g/mol, means 2 moles weighs 116.88 grams instead, since the mole-to-gram conversion depends entirely on the substance's own molar mass.

Weight conversion is essential across many disciplines, from everyday cooking and fitness tracking to scientific research and international commerce. This converter handles 21 units in a single interface, covering metric, imperial, troy, and mole-based measurements.

• Cooking: Convert recipe ingredients between ounces, grams, pounds, and kilograms when following recipes from different countries. Enter values like 3/4 pound to see the equivalent in grams for precise kitchen scale measurements.
• Jewelry: Convert between carats, troy ounces, pennyweights, and grams when evaluating gemstones or precious metals. Jewelers and appraisers regularly need to switch between troy and avoirdupois weight systems.
• Science: Convert between moles and grams using the molecular weight of a specific substance. Setting the correct molecular weight determines the mass equivalent of a given mole quantity, useful for stoichiometry calculations.
• Shipping: Convert between pounds, kilograms, short tons, long tons, and metric tons when calculating freight charges or container loads across US and metric logistics documentation.
• Fitness: Convert body weight between pounds, kilograms, and stones when tracking progress across different measurement systems. Athletes following international training programs often encounter unfamiliar units.
• Agriculture: Convert harvest yields and feed quantities between hundredweights, short tons, metric tons, and pounds. Grain markets and commodity trading frequently reference hundredweight pricing.
• Apothecary and specialty units: Convert between milligrams, micrograms, grams, and grains. The grain persists in older formulary references, ammunition charges, and precious-metal weights, where the conversion factor is often misread.
• Education: Verify homework calculations in physics, chemistry, or engineering by converting between metric and imperial mass units. Enter values in scientific notation such as 1.5e3 micrograms to explore unit relationships.