For international trading and purchase, gold is usually measured in ounces troy or metric units:
- Metric tonne (metric ton, mt) - equal to 1,000 kilograms. This is the internationally accepted measure for quantities of gold, especially gold bullion, greater than 1,000 kilograms in weight.
- Kilogram - 1,000 grams, equivalent to nnn troy ozs. Internationally accepted measure for larger quantities of gold. 1,000 kilograms = 1 metric tonne (mt).
- Gram - international measure of small quantities of gold, of the metric system. It is equivalent to 0.035274 troy ounces.
- Troy ounce - internationally accepted measure of weight for gold. A troy ounce is an avoirdupois measure. It approximates to 28.35 grams.
- Pennyweight (dwt) - a sub-unit of the avoirdupois measurement system = 24 grains or 1/20 troy ounce (1.555 grams).
- Grain - a sub-unit of the avoirdupois measurement system equivalent to 1/480 of a troy ounce (0.0648 grams).
But there are national measurements in other trading centres like Hong Kong, India, Middle East and Thailand. Each of these trading centres has gold trading traditions going back in history way before Europeans got in on the act:
- tael - (两 = chinese simp.; 兩 = chinese trad.; liǎng = pinyin) is a Far East measure of weight A tael can weigh anything between 1.18 and 1.2 troy ounces, the equivant to about 37 to 40 grams.
- tola - (तोलक = Sanskrit; तोला = Hindi; تولا = Urdu; tolā, tolaka) is a south Asian unit of mass. One Tola is the equivalent of 180 troy grains, 0.375 ounces troy. or 11.664 grams. It was traditionally the weight of 100 ratti seeds. One tola coins were produced originally because they were a convenient size and weight.
- baht - (บาท = Thai) a Thai unit of weight of about 14.6 grams.
- chi - (Vietnam) a Vietnamese unit of weight. 1 chi = 3.75g.
- don - (Korean) South Korean measurement of gold weight.
- mesghal - (پثسلاشم; Farsi) weight measurement for gold in Iran. It is the equivalent of 4.6 to 4.7 grams.