How Many Grams in an Ounce?

One avoirdupois ounce equals 28.3495 grams. This is the ounce you use for food, mail, and everything in daily life. There is also a troy ounce (31.1035 g) used exclusively for precious metals. So when gold is quoted at "$2,000 per ounce," that ounce is 10% heavier than the one on your kitchen scale.

⚖️ Ounce to Gram Conversions

⚖️ Why Are There Two Kinds of Ounces?

The avoirdupois system (from French "avoir de pois," goods of weight) became standard for trade in the 13th century. The troy system, named after Troyes, France, was used for precious metals and predates it. One troy ounce is 31.1 grams, about 10% heavier than a regular ounce (28.35 g). Confusingly, one troy pound (12 troy ounces = 373 g) is actually lighter than one avoirdupois pound (16 ounces = 454 g). The systems have coexisted for centuries because gold traders and grocers never had a reason to coordinate.

🍳 Weight Ounces vs Fluid Ounces: Are They the Same?

No, and this is one of the most common sources of confusion in cooking. When a recipe says "6 ounces of chocolate" they mean weight (put it on a scale). When it says "6 ounces of milk" they mean volume (use a liquid measuring cup). A fluid ounce of water weighs almost exactly 1 ounce, which is a convenient coincidence. But honey is denser (1 fl oz = 1.5 oz by weight) and oil is lighter (1 fl oz = 0.96 oz by weight).

📐 How Do You Convert Ounces to Grams Without a Calculator?

The simplest mental shortcut: multiply ounces by 28. Its actually 28.35, but 28 is close enough for cooking and gives you a number you can do in your head. So 4 ounces is about 112 grams, 8 ounces is about 224 grams. For more precision, multiply by 28 and then add 1% of the original (4 oz = 112 + 1.1 = 113.1, very close to the exact 113.4).

💎 What Is a Troy Ounce?

A troy ounce is 31.1035 grams, used exclusively for precious metals like gold, silver, platinum and palladium. When the news says gold is trading at $2,000 per ounce, they mean a troy ounce, which is about 10% heavier than the ounce on your kitchen scale. If you buy a "1 ounce" gold coin, it actually weighs 31.1 grams, not 28.3. This distinction matters a lot if you are investing in physical precious metals.

💎 The Troy Ounce Predates the Regular Ounce by Centuries

The troy system, still used for gold and silver, is named after Troyes, France, where it was used at the famous medieval trade fairs. It predates the avoirdupois system by at least 200 years. When you buy a "1 oz" gold coin, you are using a measurement system that European merchants standardized in the 1100s. The London Bullion Market still prices gold exclusively in troy ounces, as it has for centuries.