Weight vs. Mass
In physics, mass (measured in kilograms) is the amount of matter in an object, while weight (measured in Newtons) is the force of gravity acting on that mass. In everyday language, we use "weight" and "mass" interchangeably.
The Standard Units
- Kilogram (kg): The SI base unit of mass.
- Pound (lb): The primary mass unit in the US, defined as exactly 0.45359237 kg.
- Stone (st): Common in the UK and Ireland for body weight, equal to 14 pounds.
South Asian Weight Units
In India, Pakistan, and Nepal, traditional weights are extensively used in the gold, silver, and precious metals markets:
- Tola: Now standardized to exactly 11.6638 grams.
- Masha: 1/12th of a Tola.
- Seer & Maund: Historical units used in agriculture, where 1 Maund is 40 Seers.
East Asian Units
- Jin / Catty: A traditional Chinese and East Asian weight unit. In mainland China, it is standardized to exactly 500 grams. In Hong Kong, it is roughly 604 grams.
- Liang / Tael: Used extensively in the herbal medicine and precious metals trade (50g in mainland China).
- Momme: A Japanese unit (3.75g) still used globally to measure the quality of pearls.
European Historical
- Pood (пуд): A Russian weight unit equal to 16.38 kg, famously used to measure agricultural yields and kettlebells (girya).