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A complete reference to every weight unit used in global gold markets — from the universal troy ounce to the South Asian tola, the Thai baht, and the historical Chinese tael — with precise gram equivalents and regional context.
The troy ounce (symbol: oz t; often just "oz" in a precious metals context) is the internationally recognised unit for quoting and trading gold, silver, platinum, and palladium. It weighs exactly 31.10348 grams — approximately 10% heavier than the regular (avoirdupois) ounce used for everyday goods (28.3495 grams).
The troy system traces its origins to the medieval trading fairs of Troyes in the Champagne region of France, where a standardised system of weights facilitated commerce across Europe. The troy pound (12 troy ounces = 373.24 g) was adopted by the English Crown in 1527 for gold and silver coinage and remains the global precious metals standard more than five centuries later.
Every gold price you encounter on financial data terminals, in the LBMA benchmark publications, or on Serafa's main display is quoted in troy ounces. When Serafa shows a "per gram" or "per tola" price, it is derived from the troy ounce price by applying the exact conversion factor.
Important: Troy ounce ≠ regular ounce
1 troy oz = 31.1035 g | 1 avoirdupois oz = 28.3495 g | Difference: 9.7% — significant when calculating gold value. Always verify which ounce a price is quoted in; all reputable precious metals sources use troy ounces.
The following table lists every unit encountered in international gold markets, sorted by geographic prevalence. Highlighted rows represent units actively used in contemporary commerce.
| Unit | Symbol | Grams | Primary Region | Notes |
|---|---|---|---|---|
| Troy Ounce | oz t | 31.1035 | Global standard | The universal benchmark for gold pricing |
| Gram | g | 1.0000 | Worldwide | Most widely understood; used in everyday retail |
| Kilogram | kg | 1,000.0000 | Worldwide | Used for large bullion bars and central bank reserves |
| Tola | — | 11.6638 | India, Pakistan, Nepal, Gulf states | = 3/8 troy oz; historically tied to Indian rupee coinage |
| Vori / Bori | — | 11.6638 | Bangladesh | = 1 tola; the standard gold unit in Bangladeshi jewellery markets |
| Baht (Thai) | บาท | 15.2440 | Thailand | Standard unit of the Thai Gold Traders Association |
| Tael (Hong Kong) | 兩 (HK) | 37.4290 | Hong Kong, Macau | Chinese 'liang'; used in HK gold futures market |
| Tael (Taiwan) | 兩 (TW) | 37.5000 | Taiwan | Slightly different definition than Hong Kong tael |
| Tael (China mainland) | 两 | 50.0000 | Mainland China (historical) | 50 g definition; largely replaced by grams in modern trade |
| Monme / Momme | 匁 | 3.7500 | Japan | Traditional Japanese precious metal weight; 1/1,000 kan |
| Masha | — | 0.9720 | India, Pakistan (historical) | = 8 ratti; part of traditional Indian troy system |
| Ratti | — | 0.1215 | India (historical) | Based on Abrus precatorius seed weight; 8 ratti = 1 masha |
| Grain (Troy) | gr | 0.0648 | US, UK (historical) | 1 troy oz = 480 grains; used in historical records |
| Metric Carat | ct | 0.2000 | Gem weight (rarely for gold) | Standard gemological weight; sometimes quoted for small gold items |
The tola is the primary gold weight unit in India, Pakistan, Nepal, and Bangladesh. The word derives from Sanskrit tula, meaning scale or balance. One tola equals 11.6638 grams, a figure that traces back to the British Indian silver rupee coin, which was officially defined as one tola of silver. The Indian gold import market — one of the world's largest — still prices gold per tola in wholesale transactions, and jewellers in South Asia quote tola prices to consumers. In the Gulf, where a large South Asian diaspora resides, tola pricing is also common in local gold souks alongside per-gram quotes. The traditional Indian system subdivides further: 1 tola = 12 masha = 96 ratti, units now mostly of historical interest.
In Thailand, gold is priced and sold exclusively by the baht — not to be confused with the Thai currency of the same name. One Thai baht of gold weighs 15.244 grams. The Thai Gold Traders Association (TGTA) sets and publishes the official baht gold price daily, and all gold shops in Thailand are required to display it prominently. Thai gold jewellery is standardised at 96.5% purity (known locally as "Tong Kam Hak Haa" or 965 gold), slightly below 24K but above 23K. Thailand is the world's seventh-largest gold jewellery consumer market, and the baht weight unit is deeply embedded in the trading infrastructure.
The tael (from Malay tahil; Chinese 兩 liǎng) is a traditional Chinese weight unit with definitions that vary by region. The Hong Kong tael — used in Hong Kong's active gold futures market — equals 37.429 grams. The Taiwan tael is defined as exactly 37.5 grams. Chinese mainland's historical tael varied by dynasty and region and was eventually standardised at 50 grams by some authorities, though the gold market now uses grams. Japan uses the monme (匁, 3.75 grams), a subdivision of the traditional kan weight.
Western markets primarily operate in grams for retail jewellery (especially for lighter, decorative pieces) and troy ounces for bullion investment. The United States, Canada, and most European countries quote bullion prices in troy ounces. Retail jewellers in Western markets typically price pieces by gram weight multiplied by their store's per-gram rate — itself derived from the troy ounce spot price. The European Union's weights and measures directives have standardised retail measurements on metric (grams), making grams the dominant consumer-facing unit across Europe.
| From | To | Formula | Example |
|---|---|---|---|
| Troy Ounce | Gram | oz × 31.1035 | 2 oz = 62.207 g |
| Gram | Troy Ounce | g ÷ 31.1035 | 100 g = 3.215 oz |
| Gram | Tola | g ÷ 11.6638 | 100 g = 8.574 tola |
| Tola | Gram | tola × 11.6638 | 10 tola = 116.638 g |
| Troy Ounce | Tola | oz × 2.6667 | 1 oz = 2.667 tola |
| Baht | Gram | baht × 15.244 | 5 baht = 76.22 g |
| HK Tael | Gram | tael × 37.429 | 1 tael = 37.429 g |
| Vori | Gram | vori × 11.6638 | 10 vori = 116.638 g |
| Kilogram | Troy Ounce | kg × 32.1507 | 1 kg = 32.15 oz |
Serafa's price display and calculator use the exact conversion factors from the LBMA reference data (troy ounce → gram) and the internationally accepted tola definition (Indian Standards Institution). Thai baht and Hong Kong tael conversions follow the definitions published by the Thai Gold Traders Association and the Chinese Gold and Silver Exchange Society respectively.
A troy ounce is a unit of weight equal to 31.1035 grams, used internationally for all precious metals. It originates from the trading fairs of Troyes, France, where a standardised weight system emerged in the medieval period. The English Crown adopted it for gold and silver coinage in 1527 and the standard has persisted globally. All major gold markets — London, New York, Zurich, Shanghai — quote in troy ounces.
One tola equals exactly 11.6638 grams. It is defined as 3/8 of a troy ounce, which resolves to 11.66379... grams. The tola was originally the weight of the Indian silver rupee coin under British India's coinage standards. Today it remains the primary gold weight unit across India, Pakistan, Nepal, Bangladesh, and the Gulf states.
A troy ounce (31.1035 g) and a regular avoirdupois ounce (28.3495 g) originate from different historical weight systems. The troy system (troy pound = 12 oz = 373.24 g) predates the avoirdupois system (pound = 16 oz = 453.59 g) for precious metals commerce. The difference is about 9.7% — significant enough to cause errors if confused. All reputable gold price sources use troy ounces.
No. The Thai baht as a gold weight unit is completely separate from the Thai baht currency (THB). One gold baht weighs 15.244 grams and is the official unit of the Thai Gold Traders Association (TGTA). Thai gold shops price jewellery per baht of weight, with standard purity of 96.5% (BahtThong gold). The coincidence of names reflects that the currency baht was historically defined by silver weight.
Divide the gram weight by 11.6638. For example: 50 grams ÷ 11.6638 = 4.287 tola. To convert the other way — tola to grams — multiply by 11.6638. Serafa's calculator handles all unit conversions automatically; just select the input unit from the dropdown when calculating gold value.
Always convert to grams or troy ounces when comparing prices across countries, as these are the two globally unambiguous standards. When comparing a Gulf price quoted per tola with a European price quoted per gram, convert both to grams: 1 tola = 11.6638 g. A price of 1,400 SAR per tola equals 1,400 ÷ 11.6638 = 120.03 SAR per gram. Serafa displays all prices in multiple units simultaneously to make cross-market comparisons straightforward.
Editorial Standards: Content on this page is written and reviewed by the Serafa Editorial Team. We follow a strict fact-checking process and cite primary sources including the London Bullion Market Association (LBMA), the World Gold Council, and official assay office publications. Last reviewed: May 9, 2026.