Gold Weight Calculator
One troy ounce of gold equals 31.1035 grams, not the 28.35 grams of a regular ounce, a mix-up that has cost people real money. Gold, silver, and other precious metals are weighed in troy ounces, not the avoirdupois ounces used for food, body weight, or shipping. Mixing the two up on a 5 troy ounce coin overstates its true weight by nearly 14 grams, which matters a lot when someone is buying, selling, or insuring bullion. This gold weight calculator converts between grams, troy ounces, regular ounces, pennyweight (dwt), kilograms, and tola, the unit used across South Asia and the Middle East for gold jewelry. Enter an amount in any one of those units and see the equivalent in all the others. Add a karat purity and your own current gold price per gram or per troy ounce, and the tool also estimates the melt value of the pure gold content.
Quick answer
Gold is weighed in troy ounces, not the regular (avoirdupois) ounces used for most everyday items.
This tool does not fetch a live gold price. Enter today's price yourself from a dealer quote or spot price source, since gold prices change constantly during trading hours.
Grams
31.1035 g
Troy ounces
1
Regular ounces
1.0971
Pennyweight (dwt)
20
Kilograms
0.031103
Tola
2.6667
What this tells you
- •Gold is weighed in troy ounces, not the regular (avoirdupois) ounces used for most everyday items.
- •1 troy ounce equals 31.1034768 grams, while 1 regular ounce equals only 28.349523125 grams.
- •Pennyweight (dwt) is a jewelry-trade unit equal to 1.55517384 grams, and 20 dwt make exactly 1 troy ounce.
- •Tola is a traditional South Asian and Middle Eastern gold unit equal to 11.6638038 grams, still used for jewelry pricing today.
- •Karat measures purity, not weight. 24k gold is essentially pure, while 18k and 14k contain more alloy metal mixed in.
- •This calculator does not fetch a live gold price. You enter today's price yourself, since spot gold prices change by the minute.
How to Use
- 1Enter the amount of gold you have and choose the unit it is measured in: grams, troy ounces, regular ounces, pennyweight, kilograms, or tola.
- 2Read the converted amount across all six units at once, so you can compare a jewelry receipt in tola against a coin dealer's listing in troy ounces.
- 3If you want an estimated value, choose the karat purity of the gold. 24k is treated as 99.9% pure, 22k as 91.6%, 18k as 75%, 14k as 58.3%, and 10k as 41.7%.
- 4Enter today's gold price and pick whether you are entering the price per gram or per troy ounce. This calculator does not look up a live price, so use a current quote from a dealer or a spot price source.
- 5Read the estimated melt value, which multiplies the weight of pure gold content by your entered price. This is a starting estimate, not a quote from a buyer.
How It Works
Formula
grams = amount x conversion factor
pure gold grams = grams x purity fraction
melt value = pure gold grams x price per gramEvery unit in this calculator first converts to grams using a fixed factor: 1 troy ounce = 31.1034768 g, 1 regular ounce = 28.349523125 g, 1 pennyweight = 1.55517384 g, 1 kilogram = 1000 g, and 1 tola = 11.6638038 g. Once the amount is in grams, converting to any other unit is just dividing by that unit's own factor. For the value estimate, karat purity is expressed as a fraction of pure gold: 24k is 0.999, 22k is 0.916, 18k is 0.75, 14k is 0.583, and 10k is 0.417. Multiplying total grams by that fraction gives the weight of pure gold actually present, since jewelry and coins below 24k are alloyed with metals like copper or silver for durability. Multiplying that pure gold weight by a price per gram gives an estimated melt value. If you enter a price per troy ounce instead, the calculator first divides it by 31.1034768 to get a price per gram, then runs the same multiplication.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Convert 1 troy ounce coin to grams and tola
A standard 1 troy ounce gold coin weighs 31.1034768 grams. That same weight equals exactly 20 pennyweight, since pennyweight is defined as one-twentieth of a troy ounce, and about 2.6667 tola, since a tola is smaller than a troy ounce by roughly that ratio. Coin dealers list weight in troy ounces, but a buyer used to South Asian jewelry markets may only think in tola, so having both figures side by side avoids confusion.
Convert 10 grams of jewelry to troy ounces and regular ounces
10 grams of gold equals about 0.3215 troy ounces, the unit a dealer or appraiser would quote. It also equals about 0.3527 regular ounces, which is a slightly larger number for the same weight because a regular ounce is lighter than a troy ounce. Someone reading a jewelry receipt in grams and comparing it to a coin listed in troy ounces needs this conversion to avoid assuming the two ounce units are interchangeable.
Estimate the melt value of 10 grams of 24k gold
24k gold is treated as 99.9% pure, so 10 grams contains 9.99 grams of actual gold. At an entered price of $70 per gram, the estimated melt value is 9.99 x 70 = $699.30. This is the value of the gold content only, before any dealer premium, spread, or fabrication charge is applied.
Estimate the melt value of 5 tola of 22k gold
5 tola converts to about 58.319 grams. At 22k purity, only 91.6% of that is actual gold, which works out to about 53.4 grams of pure gold. Multiplying by $70 per gram gives an estimated melt value near $3,738. 22k is the most common purity for gold jewelry sold across South Asia and the Middle East, so this scenario matches a common real-world calculation.
Gold weight conversions and karat purity chart
Common gram amounts converted to every supported unit, plus the purity fraction used for each standard karat.
| Grams | Troy oz | Regular oz | Pennyweight (dwt) | Kilograms | Tola |
|---|---|---|---|---|---|
| 1 g | 0.0322 troy oz | 0.0353 oz | 0.643 dwt | 0.001 kg | 0.0857 tola |
| 5 g | 0.1608 troy oz | 0.1764 oz | 3.215 dwt | 0.005 kg | 0.4286 tola |
| 10 g | 0.3215 troy oz | 0.3527 oz | 6.430 dwt | 0.01 kg | 0.8574 tola |
| 50 g | 1.6076 troy oz | 1.7637 oz | 32.151 dwt | 0.05 kg | 4.2868 tola |
| 100 g | 3.2151 troy oz | 3.5274 oz | 64.301 dwt | 0.1 kg | 8.5735 tola |
Karat purity fractions used for the value calculation: 24k = 0.999, 22k = 0.916, 18k = 0.75, 14k = 0.583, 10k = 0.417.
Troy Ounce vs Regular Ounce: Why Gold Is Different
The ounce most people know from cooking or body weight is the avoirdupois ounce, equal to 28.349523125 grams, and it is part of a system where 16 ounces make a pound. Precious metals use a completely different, older system called troy weight, where a troy ounce equals 31.1034768 grams and 12 troy ounces make a troy pound. The troy system survives today almost entirely because gold, silver, platinum, and gemstones still trade in it, a holdover from medieval European trade fairs.
The practical impact is that a troy ounce is about 10% heavier than a regular ounce. A 1 troy ounce gold coin weighs 31.1035 grams, but if someone mistakenly treats that as 1 regular ounce, they would expect only 28.3495 grams, a difference of nearly 2.75 grams. On a single coin that gap seems small, but scaled up to a 100 troy ounce gold bar, the confusion is worth over 275 grams, more than half a troy ounce of gold at stake from a unit mix-up alone.
Pennyweight and tola both descend from historical trade weights that stayed in active use. Pennyweight, abbreviated dwt, is common in the US jewelry trade because it splits a troy ounce into 20 convenient parts, useful for pricing small items like rings or chains. Tola comes from the Indian subcontinent and remains the standard retail unit for gold in Pakistan, India, Bangladesh, and much of the Middle East, where jewelers quote prices per tola rather than per gram or troy ounce. Anyone comparing a US coin dealer's troy ounce price against a jewelry store's tola price needs a reliable conversion between the two, which is exactly what this calculator provides.
Common mistakes
- Confusing troy ounces with regular (avoirdupois) ounces. A troy ounce is about 10% heavier at 31.1035 grams versus 28.3495 grams, and gold, silver, and platinum are always quoted in troy ounces.
- Forgetting to apply purity when estimating melt value. 10 grams of 18k gold contains only 7.5 grams of actual gold, not 10 grams, since the rest is alloy metal added for strength.
- Assuming a live, accurate gold price is built into the tool. Gold prices move constantly during trading hours, so any value estimate is only as current as the price you type in.
- Mixing up a per-gram price with a per-troy-ounce price. A price of $2,200 makes sense as a per-troy-ounce spot price but would produce a wildly inflated result if entered as a per-gram price.
- Treating tola as a fixed, universally known unit. Some regional variants of tola differ slightly from the 11.6638038 gram figure used here, so always confirm the exact tola definition your local market uses for high-value transactions.
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