Convert Ounces to Grams

How to convert ounces to grams

Multiply ounces by 28.3495 to get grams. That factor comes straight from an exact definition: the International Yard and Pound Agreement of 1959 fixed the ounce at 1/16 lb, which is 28.349523125 g precisely, so no measurement uncertainty ever enters this conversion. The arithmetic also scales cleanly — 100 oz corresponds to 2834.9523 g.

1. Note the weight in ounces.
2. Multiply by 28.3495.
3. Round to the nearest gram if a kitchen scale is the destination.

Worked example: 4 oz of butter — one standard US stick — comes to 4 × 28.3495 = 113.3981 g on a metric scale.

What is an ounce?

An ounce, in the avoirdupois sense used for food and mail, is 1/16 of a pound and has been fixed at exactly 28.349523125 g since 1959. It anchors American recipe measurements, deli portions, and postal rates. Recipes written before digital scales became common often mix ounces with cups, which is why weight-first cooks convert everything to grams before starting. Fluid ounces, despite the shared name, measure volume and are an entirely different quantity.

What is a gram?

The gram is the metric workhorse for small weights — a thousandth of the kilogram, the SI base unit of mass whose definition the BIPM maintains. Because nearly every digital kitchen scale sold worldwide defaults to grams, this unit is the bridge between American cookbooks and the hardware sitting on most counters.

When you’ll need oz to g

• Baking American recipes on a gram scale. A 4 oz stick of butter is 113.3981 g, and the classic 12 oz bag of chocolate chips holds 340.1943 g — punch those in directly and skip the guesswork.
• Portioning food by weight. The dietitian’s familiar 3 oz serving of cooked meat is 85.0486 g, and a 5 oz can of tuna is 141.7476 g — handy when a nutrition app wants grams.
• Buying and dosing coffee. A 10 oz bag of beans is 283.4952 g; if your brew recipe is written in grams, that is the number your scale counts down from.
• Weighing mail on a metric scale. A 1 oz first-class letter is 28.3495 g, and a 2 oz letter is 56.699 g — useful when the only scale in the house shows grams.
• Small measures for tea, spices, and herbs. Half an ounce is 14.1748 g, a precision job for a gram scale rather than a measuring spoon.