Ounces to Grams: The Complete Guide
Converting ounces to grams is essential when following US recipes with a metric scale, comparing nutritional information across product labels, or working with international cooking measurements.
The Conversion Formula
grams = ounces × 28.3495For cooking: multiply by 28 for a close estimate.
Cooking Weight Reference
- 1 oz = 28.35 g
- 2 oz = 56.70 g
- 4 oz = 113.4 g
- 8 oz = 226.8 g
- 12 oz = 340.2 g
- 16 oz (1 lb) = 453.6 g
Common US Recipe Amounts
- 1 oz chocolate = 28 g
- 4 oz cream cheese = 113 g
- 8 oz mozzarella = 227 g
- 12 oz pasta = 340 g
Convert any weight instantly: Free ounces to grams converter
Complete Reference Table
- 0.5 oz = 14.175 g
- 1 oz = 28.350 g
- 2 oz = 56.699 g
- 4 oz (1/4 lb) = 113.398 g
- 8 oz (1/2 lb) = 226.796 g
- 12 oz = 340.194 g
- 16 oz (1 lb) = 453.592 g
- 32 oz (2 lb) = 907.185 g
When You Need This Conversion
Ounces-to-grams is one of the most common cooking conversions for people using American recipes. US cookbooks typically list ingredients in cups and ounces while kitchen scales in most other countries read in grams. A standard US recipe calling for "8 oz chicken breast" requires 226.8 g on a metric scale. Similarly, US supplement and protein powder labels list serving sizes in scoops and ounces, while international buyers use grams to measure doses. Postal services in many countries list weight limits in grams, making it necessary to convert package weights from US ounce-based specifications.
Common Mistakes
- Fluid ounces vs weight ounces: A recipe calling for "4 fl oz of milk" refers to volume (≈118 mL), not weight. Do not convert fluid ounces to grams using the weight formula unless you know the liquid's density.
- Rounding in baking: Baking is precise. Rounding 1 oz to 30 g instead of 28.35 g causes a 5.8% error, which can affect texture and rise in cakes and bread.
- Ounce vs troy ounce: Precious metal dealers use troy ounces (31.10 g). Standard US recipes and grocery products use avoirdupois ounces (28.35 g).
Frequently Asked Questions
How many grams in 1 ounce?
One avoirdupois ounce equals 28.3495 grams. This is the standard ounce used in everyday commerce and cooking. The troy ounce, used for precious metals, equals 31.1035 grams.
How do I convert ounces to grams without a calculator?
Multiply the number of ounces by 28 for a rough answer, then add 10% for more accuracy. For example, 4 oz × 28 = 112 g, plus 10% (11.2) = 123.2 g vs the exact 113.4 g. Alternatively, remember that 1 oz ≈ 28 g and 4 oz ≈ 113 g as reference points.
Why does the US still use ounces?
The United States retained the US customary system rather than adopting the metric system in the 1970s when most other countries metricated. Efforts to switch were attempted but met with public resistance. Today, the US is one of only three countries in the world (along with Liberia and Myanmar) that has not officially adopted SI metric as the primary measurement system.