Ounces to Grams
1 Ounce (oz) = 28.3495Gram (g)
How Many Grams in an Ounce?
One ounce equals approximately 28.35 grams. To convert ounces to grams, multiply the ounce value by 28.3495. This is one of the most essential conversions for anyone who cooks with recipes from different countries or shops at grocery stores where packaging uses metric weights. If you have ever picked up a steak at the butcher counter labeled in grams and wondered how that compares to the 6 oz portion your recipe calls for, this conversion answers that question. It is equally important for baking, where precision matters and European recipes almost always list ingredients by weight in grams rather than by volume. Useful kitchen anchors make the math faster: 1 oz = 28 g, 4 oz = 113 g, 8 oz = 227 g, and 16 oz = 454 g or 1 pound. Those benchmarks cover common portions of butter, meat, cheese, nuts, and chocolate, so you can sanity-check a package label without reaching for a calculator every time. They also help when you compare serving sizes on US nutrition labels with gram-based kitchen scales or imported packages.
How to Convert Ounce to Gram
- Start with your weight in ounces.
- Multiply the ounce value by 28.3495 to get the weight in grams.
- The result is your measurement in grams.
- For a quick mental estimate, multiply ounces by 28 or simply by 30 for a rough approximation. For example, 4 oz x 30 = 120 g (actual: 113.4 g).
- When a recipe calls for a range (e.g., 4-6 oz of chicken), convert both ends: 4 oz = 113 g and 6 oz = 170 g.
Real-World Examples
Quick Reference
| Ounce (oz) | Gram (g) |
|---|---|
| 1 | 28.3495 |
| 2 | 56.699 |
| 3 | 85.0486 |
| 5 | 141.748 |
| 10 | 283.495 |
| 15 | 425.243 |
| 20 | 566.99 |
| 25 | 708.738 |
| 50 | 1417.48 |
| 75 | 2126.21 |
| 100 | 2834.95 |
| 250 | 7087.38 |
| 500 | 14174.8 |
| 1,000 | 28349.5 |
Common Kitchen Weights: Ounces to Grams
Source: USDA National Nutrient Database
| Ounces | Grams |
|---|---|
| 1 oz | 28.3 |
| 2 oz | 56.7 |
| 4 oz | 113.4 |
| 8 oz | 226.8 |
| 12 oz | 340.2 |
| 16 oz | 453.6 |
Source: USDA National Nutrient Database
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History of Ounce and Gram
The ounce descends from the Roman "uncia," which was one-twelfth of a Roman pound. Over centuries, the ounce took on different values in different regions. The avoirdupois ounce used in cooking today was standardized in the international yard and pound agreement of 1959 at exactly 28.349523125 grams. The gram, meanwhile, was originally defined during the French Revolution as the weight of one cubic centimeter of water at its densest temperature. Today, both units are defined in terms of the kilogram, which since 2019 is anchored to the Planck constant rather than a physical artifact.
Common Mistakes to Avoid
- Confusing fluid ounces (a volume measurement) with ounces (a weight measurement). 8 fluid ounces of honey weighs far more than 8 oz because honey is denser than water. Always check whether a recipe means fl oz or oz.
- Using 30 as the conversion factor instead of 28.35. While 30 is useful for quick mental math, it introduces a 5.8% error that compounds with larger quantities. For a 16 oz measurement, using 30 gives 480 g instead of the correct 453.6 g.
- Forgetting that nutrition labels in the US list serving sizes in both ounces and grams, but the gram value is often rounded. Always use the conversion factor rather than relying on rounded label values.
- Rounding each ingredient too early when converting several ounce-based measurements in the same recipe. Keep at least one decimal place until the end so small rounding errors do not add up across flour, butter, nuts, and chocolate.
Frequently Asked Questions
Is the ounce used in cooking the same as a troy ounce?
Why do recipes use ounces instead of grams?
How do I convert ounces to grams without a calculator?
Should I measure ingredients by weight or volume for baking?
How many grams is 8 ounces?
When grocery shopping, remember these common serving size benchmarks: a typical chicken breast is 6-8 oz (170-227 g), a standard burger patty is 4 oz (113 g), and a recommended serving of meat is 3 oz (85 g), which is roughly the size of a deck of cards.
A loaf of bread ≈ 450 g (1 lb). A gallon of water ≈ 3.78 kg (8.34 lb). An average adult ≈ 70–80 kg (154–176 lb). A compact car ≈ 1,400 kg (3,086 lb).
Further Reading
Sources & References
- NIST — Units and Conversion Factors — Official US unit conversion factors from the National Institute of Standards and Technology.
- BIPM — The International System of Units (SI) — SI unit definitions from the International Bureau of Weights and Measures.