The gram-to-ounce conversion calculator is a fast, accurate weight converter built for nutrition tracking, recipe scaling, and everyday kitchen use. Whether you are converting a 500 g bag of flour to ounces, logging a 6 oz chicken breast in grams, or scaling a recipe from metric to imperial, this tool handles it instantly.
Because nutrition labels around the world use different weight systems, having one reliable converter makes meal prep simpler. Cooks, dietitians, gym-goers, and home bakers all benefit from knowing exactly how many ounces are in a gram and vice versa. The calculator supports grams, kilograms, milligrams, ounces, and pounds, so it is equally at home in the kitchen, at the grocery store, and in macro-tracking workflows. It also shows a two-step breakdown, so you can see the conversion math behind every result.
Use the preset buttons to load common amounts instantly: 28.35 g (1 oz), 100 g, 250 g, or 453.6 g (1 lb). Choose your decimal precision, and the result will be ready for recipe notes, food journal entries, or nutrition labels. If you work with food portions on a regular basis, this converter saves time and keeps your numbers consistent.
Convert Between Grams & Ounces
Enter any weight, pick its current unit, then choose the unit you want. The result appears with a clear two-step breakdown.
⚖️ The Conversion Formula
An international avoirdupois ounce is defined as exactly 28.349523125 grams. This value comes from the definition of the international avoirdupois pound (1 lb = 453.59237 g) divided by the 16 ounces in a pound. The same relationship is used in official weights and measures standards, including the reference material maintained by the U.S. National Institute of Standards and Technology (NIST SI mass page), so the conversion is exact rather than approximate.
Ounces to grams: ounces × 28.349523125 = grams
For casual cooking, many recipes round 1 ounce to 28 g. That is fine for eyeballing portions. But in calorie and macro tracking, small rounding errors add up across every ingredient you log. For the most accurate nutrition totals, use 28.35 g per ounce or the exact figure above.
Quick Reference Table
| Grams | Ounces | Grams | Ounces |
|---|---|---|---|
| 1 g | 0.035 oz | 100 g | 3.527 oz |
| 5 g | 0.176 oz | 150 g | 5.291 oz |
| 10 g | 0.353 oz | 200 g | 7.055 oz |
| 15 g | 0.529 oz | 250 g | 8.818 oz |
| 20 g | 0.705 oz | 300 g | 10.582 oz |
| 25 g | 0.882 oz | 400 g | 14.110 oz |
| 30 g | 1.058 oz | 500 g | 17.637 oz |
| 50 g | 1.764 oz | 1000 g | 35.274 oz |
Values are rounded to three decimal places using the exact 28.349523125 g/oz relationship. For reference, 1 kilogram is about 35.274 oz or 2.2046 lb, so the same table can help when comparing bulk package sizes.
How to Use This Tool
- Enter the weight you want to convert in the number field.
- Select the unit of that number from the first dropdown: g, kg, mg, oz, or lb.
- Select the unit you want the answer in from the second dropdown.
- Choose how many decimal places to show. Two is usually enough for food labels; four gives near-laboratory precision.
- Click Convert and read the result. The breakdown below shows the intermediate gram value so you can verify the math.
The preset buttons load common household weights like 100 g or 453.6 g (1 lb), so you can test the converter without typing. If you prefer to type your own value, the number field accepts decimals, which makes it easy to convert awkward quantities like 0.75 lb or 350 g.
Worked Examples
Example 1: Flour for a recipe. The recipe calls for 85 g of flour. How many ounces is that? 85 ÷ 28.34952 = 2.998 oz, which rounds to about 3 oz. A kitchen scale that reads 28 g per ounce would give the same practical answer.
Example 2: Protein in chicken. A chicken breast weighs 6 oz. To log it in grams, multiply: 6 × 28.34952 = 170.097 g, so round to 170 g. This is a common conversion for meal-prep containers that are labeled in ounces but tracked in grams.
Example 3: Bulk oats. A package says 250 g per serving. In ounces that is 250 ÷ 28.34952 = 8.818 oz, just over half a pound. If you are following a recipe that lists oats in cups, remember that this converter handles weight, not volume.
Notice how each example follows the same pattern: multiply or divide by 28.34952. The calculator makes this automatic, but understanding the relationship helps you spot unreasonable results, such as a serving that unexpectedly jumps from 30 g to 30 oz.
Precision Notes & Common Mistakes
- Do not confuse weight ounces with fluid ounces. A fluid ounce measures volume, not weight. One fluid ounce of water weighs about 1.043 oz, but oil, honey, and cream all weigh differently. This calculator works with weight ounces, which are the ounces used on nutrition labels and kitchen scales.
- Use the decimal, not the rounded shortcut, when tracking macros. Using 28 g instead of 28.35 g introduces a 1.2% error. That might not matter for a single 30 g portion, but it can skew a weekly meal plan because the error repeats for every serving you log.
- Weigh foods before cooking for the most consistent data. Cooked foods lose water weight. If the nutrition label lists raw weight, weigh your ingredient raw and convert that raw amount.
- Check the label. In the U.S., nutrition facts panels list grams by weight. Many imported labels show both grams and ounces, but the ounce figure may be rounded to a convenient serving size.
- Tare your scale. Place a container on the scale, press tare, then add the food so you are not accidentally counting the weight of the bowl.
Frequently Asked Questions
Is 28 g or 28.35 g the correct ounce?
Officially, 1 oz = 28.349523125 g. The 28 g shortcut is only an approximation. For food labels and nutrition tracking, 28.35 g per ounce is the standard level of precision.
How do I convert ounces back to grams?
Multiply the ounce value by 28.34952. For example, 4 oz × 28.34952 = 113.398 g, which most people round to 113 g for a serving size.
Why are some nutrition labels in grams and others in ounces?
Metric labeling is standard in most countries, while the U.S. often allows or requires both units. The conversion makes it easy to compare products from different markets without guessing.
What is 100 g in ounces?
100 g ÷ 28.34952 = 3.527 oz, or about 3½ ounces. This is a frequent question for protein bars, snacks, and single-serving packages.
What about milligram amounts?
1,000 mg = 1 g, so 1,000 mg is about 0.035 oz. Milligrams are more common for micronutrients like sodium, potassium, and calcium than for whole foods.
Do I need a food scale to use this converter?
A scale gives accurate starting weights. If you do not have one, you can still use package weights. Measuring cups for solids can vary by 10–20%, so a food scale paired with this converter is the most reliable route for meal prep and macro tracking.