About

In precious metal trading, precision is financial safety. The "Troy Ounce" is the global standard for weighing gold, silver, and platinum, yet it is frequently confused with the standard "kitchen" ounce (avoirdupois). A standard ounce is 28.35 grams, while a Troy ounce is roughly 10% heavier at 31.10 grams. Confusing these units can lead to significant valuation errors in investment portfolios or jewelry fabrication. This tool utilizes the exact definition of the Troy ounce to provide conversion accuracy up to four decimal places.

Formulas

The conversion is a direct multiplication using the internationally fixed standard for the Troy system.

m_grams = m_troy × 31.1034768

Note: 1 oz t ≈ 1.097 oz (avdp)

Reference Data

Unit	Weight in Grams g	Weight in Grains gr
1 Troy Ounce (oz t)	31.1035	480
1 Standard Ounce (oz)	28.3495	437.5
1 Tola (South Asia)	11.6638	180
1 Baht (Thailand)	15.2441	235.2
1 Tael (Hong Kong)	37.4290	577.6
1 Pennyweight (dwt)	1.5552	24

Frequently Asked Questions

The Troy system dates back to the Middle Ages (Troyes, France) and was retained for precious metals while the rest of the world moved to Avoirdupois for general goods. The Troy pound contains 12 ounces, while the standard pound contains 16, resulting in different ounce weights.

The unit of weight applies to the physical object regardless of purity. However, the "value" depends on purity. If you have 1 Troy ounce of 18k gold, the *weight* is 31.1g, but the *pure gold content* is only 75% of that weight.

"dwt" stands for Pennyweight. It is commonly used in dentistry and jewelry casting. There are 20 pennyweights in 1 Troy ounce.

Only if your scale can measure in grams. If you set a kitchen scale to "oz", it measures standard ounces (28.35g). You must manually convert that reading to Troy ounces, or you will underestimate your gold's weight.