Why is 1 ounce not a round number of grams?

Ounces developed historically in various ways. The avoirdupois ounce (28.35 g) was standardized long before the metric system, so the conversion isn't a round number. The reverse conversion is just as useful for going the other direction.

Should I use ounces or grams for cooking?

Either unit can express mass accurately; precision depends on the scale and rounding. Grams often avoid fractions of an ounce, which can be convenient for small baking quantities.

A recipe calls for 10 ounces of chocolate. How many grams should I use?

10 ounces ≈ 283.5 grams. Weigh 283.5 g, or round only as much as the recipe permits; substituting 300 g would add about 5.8%.

I found a recipe that uses ounces, but my kitchen scale only shows grams. How do I convert?

Multiply ounces by 28.35 to get grams. Or use common conversions: 1 oz ≈ 28g, 2 oz ≈ 57g, 4 oz ≈ 113g, 8 oz ≈ 227g. For larger quantities in pounds, check [lbs to kg]({/weight/lbs-to-kg/}).

Ounces to Grams Converter

Enter a value to instantly convert between weight units.

From

Precision4 dp

1 Ounce = 28.3495 Gram

Key Formulas

Kilogram → Pound

lb = kg × 2.20462

Pound → Kilogram

kg = lb × 0.453592

Gram → Ounce

oz = g × 0.035274

Ounce → Gram

g = oz × 28.3495

Formula

g = oz × 28.34952

US recipes and package labels may state mass in avoirdupois ounces, while metric kitchen scales and nutrition labels use grams. Convert ounces to grams when weighing the same ingredient or product on a gram-only scale; fluid ounces measure volume and are not part of this conversion.

Source: NIST SP 811, Appendix B.9

Reviewed by the Convert Calc editorial team · Last reviewed: 2026-08-01 · see our methodology

Frequently Asked Questions

Real-World Examples

A one-ounce package portion weighs about 28.35 grams on a metric scale.

1 oz = 28.35 g

4 ounces of flour is roughly 113 grams for baking recipes

4 oz = 113.4 g

1 pound (16 ounces) equals 453.59 grams

16 oz = 453.59 g

8 ounces (half a pound) equals 226.8 grams, common for chocolate or butter in recipes

8 oz = 226.8 g

kg to lbs lbs to kg grams to ounces kg to grams stone to kg

See This in Context

Cooking Science & Lab Baking Ingredient Weight Chart: Cups to Grams