16 GOLD WEIGHT DEFINITIONS + LIVE METAL VALUE
Convert gold weight without mixing incompatible ounces, taels or baht units
Convert an amount between metric, troy, ordinary avoirdupois and regional gold-market units. Every result passes through a visible grams-per-unit factor. The tool keeps a troy ounce separate from an ordinary ounce, distinguishes Hong Kong and Taiwan taels, and treats Thai bullion and jewelry baht weights as different definitions. Add fineness only when you want contained gold and live metal value.
Price reference
Shows the source and observation time of the metal price used here. Product premiums, dealer quotes and taxes are separate.
- Source
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- Observed
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- Age
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- Delivery
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Checking the current market reference.
Apply fineness after converting mass
Weight conversion does not change purity. Enter the item's fineness to calculate contained gold and a live metal reference.
One input across all supported units
| Unit | Equivalent | Grams per unit | Definition |
|---|---|---|---|
| MilligramMetric · mg | 31,103.4768 mg | 0.001 g | One thousandth of a gram. |
| GramMetric · g | 31.1034768 g | 1 g | SI metric reference unit used by this calculator. |
| KilogramMetric · kg | 0.0311034768 kg | 1,000 g | 1,000 grams. |
| GrainTroy · gr | 480 gr | 0.06479891 g | 1/480 of a troy ounce. |
| PennyweightTroy · dwt | 20 dwt | 1.55517384 g | 24 grains or 1/20 troy ounce. |
| Troy ounceTroy · oz t | 1 oz t | 31.1034768 g | Precious-metals ounce; not the ordinary ounce. |
| Troy poundTroy · lb t | 0.083333333333 lb t | 373.2417216 g | 12 troy ounces. |
| Ordinary ounce (avoirdupois)Avoirdupois · oz av | 1.0971428571 oz av | 28.349523125 g | The common household ounce; not a troy ounce. |
| Ordinary pound (avoirdupois)Avoirdupois · lb av | 0.068571428571 lb av | 453.59237 g | 16 ordinary ounces. |
| TolaSouth Asia · tola | 2.6666666667 tola | 11.6638038 g | Reference convention: 3/8 troy ounce. |
| Vori / BhoriSouth Asia · vori | 2.6666666667 vori | 11.6638038 g | Bangladesh market name using the calculator's tola-equivalent convention. |
| Hong Kong troy taelEast Asia · HK tael | 0.830999406877 HK tael | 37.429 g | Hong Kong precious-metals troy tael. |
| Hong Kong troy maceEast Asia · HK mace | 8.3099940688 HK mace | 3.7429 g | 1/10 Hong Kong troy tael. |
| Taiwan taelEast Asia · TW tael | 0.829426048 TW tael | 37.5 g | Regional 37.5-gram convention; do not substitute for Hong Kong tael. |
| Thai baht weight — bullionThailand · baht bar | 2.0403750197 baht bar | 15.244 g | Thai gold-bar weight reference. |
| Thai baht weight — jewelryThailand · baht jewelry | 2.0516805277 baht jewelry | 15.16 g | Thai gold-jewelry weight reference; differs from bullion. |
A calculated match does not verify a scale, hallmark, fineness or product. For a material transaction, confirm the unit convention printed on the quote and use a suitable calibrated scale.
The gold weight conversion formula
GoldObserve uses grams as the neutral bridge. Multiply the source amount by its grams-per-unit factor, then divide by the target unit's factor. This keeps every pairwise result traceable instead of maintaining hundreds of independent conversion constants.
Pure-gold grams = converted gross grams × fineness ÷ 1,000. Metal value = pure-gold troy ounces × spot per troy ounce.
Select the exact source unitDo not choose ordinary ounce when the label says troy ounce.
Convert the source to gramsAmount × the displayed source gram factor.
Convert grams to the targetGram mass ÷ the displayed target gram factor.
Apply purity separatelyFineness changes contained gold, not the gross mass conversion.
Troy ounce vs ordinary ounce
Gold and other precious metals are normally quoted in troy ounces. The London Bullion Market Association gives one troy ounce as exactly 31.1034768 grams and describes the troy relationships: 24 grains per pennyweight and 20 pennyweights per troy ounce. That means one troy ounce contains 480 grains.
An ordinary or avoirdupois ounce is 28.349523125 grams. It is the ounce used for many everyday goods, but it is not interchangeable with a precious-metals troy ounce. The NIST precious-metals conversion guidance specifically uses troy or SI units for weight-based precious-metals sales and provides comparison factors for grams, pennyweights and troy ounces.
Regional gold units need the region in the name
“Tael” is not one universal mass. This calculator labels Hong Kong troy tael as 37.429 grams and Taiwan tael as 37.5 grams so they cannot silently substitute for each other. Historical Hong Kong legislation recorded one tael troy as 37.429 grams, with one troy mace equal to one tenth of that tael.
Tola and vori are both calculated here with the declared 3/8-troy-ounce reference, equal to 11.6638038 grams. Local trade documents can round or define traditional units differently, so use the factor printed on an actual receipt, scale or exchange specification when it conflicts with a general converter.
Thai gold bullion and jewelry use different baht weights
Baht can mean Thailand's currency or a traditional gold weight. The Thai Gold Traders Association states that one baht of gold bullion weighs 15.244 grams while one baht of gold jewelry weighs 15.16 grams. The Singapore Bullion Market Association's Thailand market overview also describes baht as the standard gold unit and gives the 15.244-gram bullion reference.
Weight is still not purity. Thai gold products are often discussed together with local fineness conventions, but this converter never infers purity from the unit name. Enter the verified fineness separately before using the optional pure-gold or metal-value result.
For the full THB workflow, use the Thailand gold price and baht-weight guide, which separates the international metal reference, local product convention, shop ask and buyback.
How to use a gold weight result safely
- Read the full unit name on the quote; “oz” alone does not prove troy or ordinary ounce.
- Separate gross weight from fine-gold weight and from purity or Karat.
- Confirm whether a regional unit applies to bullion, jewelry or another local convention.
- Keep enough decimal precision until the final display or settlement step.
- Compare the scale's unit indicator with the unit entered into the worksheet.
- For a material transaction, use suitable calibrated equipment and the governing trade specification.
Frequently asked questions
How many grams are in one troy ounce of gold?
One troy ounce is exactly 31.1034768 grams. The same conversion applies to mass regardless of the gold's purity.
Is one ounce of gold 28.35 grams?
No, not when ounce means troy ounce. About 28.35 grams is an ordinary avoirdupois ounce; precious-metal quotations normally use the 31.1034768-gram troy ounce.
How many pennyweights are in a troy ounce?
There are 20 pennyweights in one troy ounce. Each pennyweight contains 24 grains.
Is every tael 37.5 grams?
No. Regional definitions differ. This tool separates the 37.429-gram Hong Kong troy tael from the 37.5-gram Taiwan reference.
Is a Thai gold baht the same for bars and jewelry?
No. The tool uses 15.244 grams for Thai bullion baht weight and 15.16 grams for Thai jewelry baht weight.
Does converting weight calculate pure gold automatically?
Only after you enter fineness. The base conversion reports gross mass; the optional value panel applies fineness separately.
Can this tool verify a gold item?
No. It cannot verify scale calibration, weight markings, purity, authenticity, title or transaction terms.