How to use this converter
What this category measures
Mass measures the amount of matter, while weight is the force produced by gravity acting on that mass. Everyday tools often use the words interchangeably, so this page keeps common mass and trade units together while making the distinction available for technical work.
Where these conversions help
Use grams and kilograms for recipes, laboratory notes, shipping, and general metric work. Pounds, ounces, stone, tons, carats, and grains are useful when a product label, commercial document, health record, or regional specification uses customary units.
How results are calculated
RulerUnit uses the kilogram-based metric system as the reference and applies standard mass factors for each supported unit. A pound is treated as exactly 0.45359237 kilograms, while metric and US or imperial ton entries remain separate so regional definitions are not silently mixed.