Ounces to Grams: How to Convert Weights Accurately Every Time
By the Super Simple Digital Tools Team · Updated June 2026
Ounces and grams belong to two different measurement systems: ounces are part of the imperial and US customary world, while grams are the base of the metric system used across most of the planet and in nearly all scientific work. When a recipe, parcel, or product label mixes the two, you need a reliable bridge between them. The good news is that the conversion is fixed and simple: one international ounce is defined as exactly 28.349523125 grams, a relationship that never changes regardless of what you are weighing.
To convert, multiply the number of ounces by 28.3495. If a recipe calls for 12 ounces of chocolate, that is 12 x 28.3495, or about 340 grams. The reverse is just as easy: divide grams by 28.3495 to find ounces, so 500 g comes out to roughly 17.6 oz. Memorizing a few anchor values makes life faster in the kitchen, where 4 oz is about 113 g, 8 oz is about 227 g, and a full pound (16 oz) is about 454 g.
Many cooks who own a metric scale prefer to work in grams even when a recipe is written in ounces, and there is a real reason for it. Grams are a smaller, finer unit, so they let you hit a target weight more precisely than rounding to the nearest quarter ounce. In baking especially, where ratios of flour, sugar, fat, and leavening drive the final texture, a difference of just a few grams can shift a result from soft to dry. Converting to grams and weighing on a scale removes the guesswork that measuring cups introduce.
Two pitfalls cause most conversion mistakes. The first is confusing weight ounces with fluid ounces; a fluid ounce measures volume, and turning it into grams requires knowing the density of the specific liquid, so this tool is not the right one for that. The second is the troy ounce, used only for precious metals such as gold and silver. A troy ounce is about 31.1035 grams, roughly ten percent more than the everyday ounce, so using the standard factor on bullion will undercount its weight.
For everything else, food, postage, craft materials, supplements, and general goods, the standard avoirdupois ounce and the 28.3495 factor are exactly what you want. Type your figure into the converter and you get an answer in a moment, calculated right in your browser so nothing you enter is uploaded or saved. Keep the common anchor values in mind for quick sanity checks, and you will rarely need to reach for a calculator again.
- Anchor your memory with 16 oz = ~454 g (one pound); halve it for 8 oz (~227 g) and quarter it for 4 oz (~113 g) to estimate kitchen weights fast.
- For precise baking, switch the whole recipe to grams once and weigh on a scale rather than converting each ingredient mid-bake, which compounds rounding errors.
- Before converting gold, silver, or coins, confirm whether the figure is in troy ounces (~31.1 g) and use a troy-specific tool instead of this one.
- If a label says 'fl oz', stop: that is volume, not weight, and needs the liquid's density, so a plain ounce-to-gram conversion will be wrong.