Troy Ounce vs. Avoirdupois Ounce
A Troy Ounce (ozt) is 9.71% heavier than a regular standard grocery ounce (oz). Understand the difference to avoid financial loss when trading gold, silver, and precious metals.
Interactive Live Ounce Comparison Calculator
Troy Ounce (ozt) vs. Regular Ounce (oz)
| Property | Troy Ounce (ozt) | Avoirdupois Ounce (oz) |
|---|---|---|
| Exact Mass in Grams | 31.1034768 grams | 28.349523125 grams |
| Mass in Grains (gr) | 480 grains | 437.5 grains |
| Ounces per Pound | 12 troy ounces per Troy Pound (373.24g) | 16 ounces per Standard Pound (453.59g) |
| Primary Industry Use | Gold bullion, Silver, Platinum, Palladium, Assay | Grocery items, Post packages, Body weight, General items |
| Official ISO Symbol | ozt (also XAU for 1 oz Gold) |
oz (Avoirdupois) |
Why do we use Troy Ounces for Gold?
The Troy system dates back to the Middle Ages from the trade market of Troyes, France. In 1527, England made it the official standard for gold and silver coinage. To this day, all major bullion exchanges (LBMA, COMEX, Shanghai Gold Exchange) quote spot gold prices strictly in Troy Ounces.
The Costly Mistake to Avoid
If you purchase 10 ounces of gold measured on a standard kitchen or postal scale (28.35g each = 283.5g total), you actually receive 27.5 grams less gold than 10 true Troy Ounces (311.0g). At $2,000/oz gold price, that mistake can cost you over $1,700!
🔗 Related Bullion & Precision Weight Converters
Calculating fine gold scrap or jewelry melt values? Assess alloy purity with our Gold Karat & Fine Melt Weight Calculator. For South Asian traditional gold trade, convert directly using our Tola to Grams Gold Converter, or clear up gemstone vs alloy terminology in Carat vs Karat Differences.
Need everyday pantry weights? Use Grams to Ounces or convert all 19 systems at once on our Live Conversion Matrix and Universal Converter. LBMA and NIST definitions are detailed in our Scientific Methodology.