How Many Grams Are in an Ounce?

There are 28.3495 grams in 1 ounce. This is the avoirdupois ounce, the everyday weight ounce used for food, and its value is fixed by international agreement, not an approximation. For most cooking you can round to 28 grams without any meaningful error, but if you need precision, use the full figure of 28.3495. Going the other way, 1 gram is about 0.035 ounces.

Ounce to gram conversion table

Here are the weights you will meet most often in the kitchen:

Weight ounces vs. fluid ounces

This is the trap. The gram conversion above applies only to weight ounces, the kind you read on a scale. A fluid ounce is a completely different unit that measures volume, roughly 29.57 ml for the US fluid ounce. You cannot convert fluid ounces directly to grams without knowing what the ingredient is, because a fluid ounce of oil weighs less than a fluid ounce of honey. If your recipe says “4 oz of butter,” that is a weight and 4 x 28.35 gives about 113 grams. If it says “4 fl oz of milk,” that is a volume. Our guide to how many ounces are in a cup unpacks that difference in detail.

Why grams win for baking

Grams are simply more precise than ounces for small quantities, because a gram is a finer unit. When a recipe needs 7 grams of yeast or 3 grams of salt, expressing that in ounces gives awkward decimals like 0.25 oz that are hard to measure accurately on most home scales. That is why serious baking recipes, especially for bread and pastry, list grams first. A digital scale that reads in single grams costs very little and removes the rounding errors that creep in when you convert back and forth.

Pounds and larger weights

Once you pass 16 ounces you are into pounds. One pound is 16 ounces, or about 453.6 grams, and a kilogram is about 2.2 pounds. For meat and produce this matters: a “2 pound roast” is roughly 907 grams, and a recipe calling for 500 grams of ground beef is close to 1.1 pounds. Keeping the anchor “1 pound is about 454 grams” in mind lets you translate package labels on the fly.

The troy ounce trap

You may see “ounce” used for gold and silver, but that is the troy ounce, a different unit entirely at about 31.10 grams. It survives only in the precious-metals trade and has no place in the kitchen. If a source mixes up troy and avoirdupois ounces, weights will be off by about 10 percent, so for any food conversion always use the standard 28.35 grams per ounce.

Using a kitchen scale well

A scale only helps if you use the tare button. Place your empty bowl on the scale, press tare to reset it to zero, then add the ingredient and read its true weight, with the bowl subtracted automatically. You can tare again between ingredients to weigh several things into the same bowl one after another, which is how bakers build a dough with a single vessel and no cup to wash. Switch the scale to grams for anything under a few ounces, since the finer unit gives you readings you can actually hit accurately.

Common food weights to recognize

A few weights come up so often they are worth knowing by feel. A standard stick of US butter is 4 ounces, about 113 grams. A typical can of beans or tomatoes is around 14 to 15 ounces, roughly 400 grams. A large egg out of its shell weighs close to 2 ounces, about 50 grams. Recognizing these helps you sanity-check a conversion: if your math says a stick of butter is 300 grams, you know something went wrong.

These anchors also make substitutions easier. If a European recipe asks for 100 grams of chocolate and your bar is sold in ounces, you know 100 grams is a little over 3.5 ounces, so most of a 4-ounce bar. If a recipe wants 250 grams of flour and you think in cups, that is close to 2 cups of all-purpose flour by the common 120-grams-per-cup figure. Keeping a couple of these reference points in mind lets you move between the two systems without stopping to calculate every time.

Quick mental math

To convert ounces to grams in your head, multiply by 28 and add a little. For 5 ounces, 5 x 28 is 140, plus a couple of grams for the rounding gives about 142 (the exact figure is 141.7). To go from grams back to ounces, divide by 28. It is rough, but close enough to know whether you are in the right ballpark before you reach for a scale. When you need volume rather than weight, see our guides to tablespoons in a cup and milliliters in a cup.

The bottom line

An ounce is 28.3495 grams, and a pound is about 454 grams. Just remember that this only applies to weight ounces, never fluid ounces, and that for anything requiring real accuracy, weighing in grams beats measuring in ounces every time.