How to Convert Ounces to Grams
The conversion is straightforward: multiply the weight in ounces by 28.3495. This factor comes from the international definition of the avoirdupois ounce, which is exactly 1/16 of a pound (0.45359237 kg / 16 = 0.028349523 kg = 28.3495 g). For everyday calculations, rounding to 28.35 or even 28 gives results accurate enough for cooking and general use.
Leah Novak converts between ounces and grams daily at Rise and Shine Bakery. Her American recipes call for ingredients in ounces and cups, while European recipes she adapts use grams. A croissant recipe requiring 8 oz of butter converts to 8 x 28.35 = 226.80 g. She finds gram measurements more consistent, since a cup of flour can vary by 30 g depending on how it is scooped, but 120 g is always 120 g on a scale.
Ounces to Grams Reference Table
This table covers the range from fractions of an ounce through 16 ounces (one pound). These are the weights most commonly encountered in cooking, baking, and small package shipping.
| Ounces (oz) | Grams (g) | Common Example |
|---|---|---|
| 0.25 | 7.09 | Packet of yeast |
| 0.5 | 14.17 | Tablespoon of butter |
| 1 | 28.35 | Slice of bread |
| 2 | 56.70 | Small chocolate bar |
| 3 | 85.05 | Deck of cards |
| 4 | 113.40 | Stick of butter |
| 5 | 141.75 | Medium apple |
| 6 | 170.10 | Chicken breast |
| 8 | 226.80 | Cup of flour (approx) |
| 10 | 283.50 | Can of soup |
| 12 | 340.19 | Can of soda |
| 16 | 453.59 | One pound |
When Do You Need to Convert Ounces to Grams?
Ounce-to-gram conversions are most common in cooking, baking, postal shipping, and jewelry. Any time you cross between American recipes and metric ones, or ship something internationally, this conversion becomes necessary.
Baking and Cooking
Leah Novak's signature sourdough recipe calls for 17.5 oz of bread flour. When she scales up for Marco Ferreira's restaurant order, she converts to grams first: 17.5 x 28.35 = 496.13 g, which she rounds to 500 g for a clean metric batch. Scaling in grams is easier because the math stays simple. Doubling the recipe becomes 1,000 g instead of 35 oz, and tripling becomes 1,500 g instead of 52.5 oz.
Postal and Shipping
USPS First-Class Mail pricing changes at 1 oz increments, but international postal services often use grams. A letter weighing 0.8 oz converts to 0.8 x 28.35 = 22.68 g. Priya Patel ships promotional materials to international clients for Sam Okafor's real estate business. She weighs packages in ounces on her office scale and converts to grams for the customs declaration form.
Jewelry and Precious Metals
Note that jewelry and precious metals use troy ounces (31.1035 g), not standard ounces. If you are converting gold, silver, or platinum weights, use 31.1 g per troy ounce. This calculator uses standard (avoirdupois) ounces at 28.3495 g. Tom Brewer, a hobbyist coin collector, reminds Maya Singh of this distinction whenever she helps catalog his collection for an inventory spreadsheet.
Nutrition Labels
US nutrition labels list serving sizes in grams and ounces. A serving of cheese might be listed as "1 oz (28 g)." Understanding this equivalence helps when comparing products or tracking macros. Marco compares ingredient costs per gram across suppliers, since some quote by the ounce and others by the gram.
Baking Ingredients by Weight
Volume measurements (cups, tablespoons) are unreliable for baking because different ingredients have different densities. One cup of flour can weigh anywhere from 120 g to 160 g depending on how it is measured. Professional bakers like Leah weigh everything in grams. Here is a reference table for common baking ingredients.
| Ingredient | 1 oz | 1 Cup (approx g) | 1 Cup (approx oz) |
|---|---|---|---|
| All-purpose flour | 28.35 g | 125 g | 4.4 oz |
| Bread flour | 28.35 g | 130 g | 4.6 oz |
| Granulated sugar | 28.35 g | 200 g | 7.1 oz |
| Brown sugar (packed) | 28.35 g | 220 g | 7.8 oz |
| Butter | 28.35 g | 227 g | 8.0 oz |
| Cocoa powder | 28.35 g | 85 g | 3.0 oz |
| Rolled oats | 28.35 g | 90 g | 3.2 oz |
| Honey | 28.35 g | 340 g | 12.0 oz |
Ounces vs. Troy Ounces vs. Fluid Ounces
The English language uses the word "ounce" for three different measurements, which causes frequent confusion. Understanding the differences prevents costly mistakes, especially when buying precious metals or following recipes.
Avoirdupois ounce (oz): 28.3495 grams. This is the standard ounce used for food, shipping, body weight, and most everyday purposes. When a recipe says "6 oz of chicken," it means avoirdupois ounces. This is what the calculator on this page converts.
Troy ounce (oz t): 31.1035 grams. Used exclusively for precious metals. When gold is quoted at "$2,300 per ounce," that means per troy ounce. A troy ounce is about 10% heavier than a regular ounce. Buying gold at the "regular ounce" price would mean overpaying by roughly 10%.
Fluid ounce (fl oz): a unit of volume, not weight, equal to about 29.57 mL. One fluid ounce of water happens to weigh close to one avoirdupois ounce (about 29.6 g vs 28.35 g), but this coincidence does not hold for other liquids. One fluid ounce of olive oil weighs about 27 g, while one fluid ounce of honey weighs about 42 g.