Grams to Fl Oz Converter
Convert grams to US fluid ounces. Grams are weight and fluid ounces are volume, so pick your substance — water, whole milk, vegetable oil, all-purpose flour, granulated sugar, honey, or butter — enter grams, and get fluid ounces plus milliliters and cups.
Example: with Weight in grams 250 · Substance Water (1.00 g/mL) → Fluid ounces: 8.45 fl oz.
- In milliliters250 mL
- In US cups1.06 cups
- How it converts250 g ÷ 1 g/mL = 250 mL; ÷ 29.5735 = 8.45 fl oz
Computed by the calculator below using its default values. Change any input to see your own numbers.
fl oz = grams ÷ density (g/mL) ÷ 29.5735. Water converts nearly 1:1 gram to mL; flour needs almost twice the volume for the same weight.
Why grams to fluid ounces needs a density
A gram is a unit of weight; a fluid ounce is 29.5735 milliliters of space. The bridge between them is density — how many grams fit in each milliliter. Water sits at about 1 g/mL, which is why 250 g of water is almost exactly 250 mL, or 8.45 fluid ounces. Everything else in the kitchen departs from that anchor.
Dry ingredients trap air, so they are lighter per milliliter: all-purpose flour runs about 0.53 g/mL, meaning 100 g of flour fills 6.38 fluid ounces — nearly double water's 3.38. Honey goes the other way at roughly 1.42 g/mL, packing 100 g into just 2.38 fluid ounces. Pick the wrong substance and the answer can be off by a factor of two.
How it’s calculated
Fluid ounces = grams ÷ density (g/mL) ÷ 29.5735 mL per US fl oz. Cups use 1 US cup = 236.588 mL. Densities used: water 1.00, whole milk 1.03, vegetable oil 0.92, all-purpose flour 0.53, granulated sugar 0.85, honey 1.42, butter 0.955 g/mL. Volume factors are NIST values.
Densities are approximate and shift with temperature, humidity, and packing — scooped versus sifted flour alone can differ by 20 percent, so treat results as close kitchen estimates.
Approximate densities and what 100 g fills
| Substance | Density (g/mL) | 100 g in fluid ounces |
|---|---|---|
| Water | 1.00 | 3.38 fl oz |
| Whole milk | 1.03 | 3.28 fl oz |
| Vegetable oil | 0.92 | 3.68 fl oz |
| All-purpose flour | 0.53 | 6.38 fl oz |
| Granulated sugar | 0.85 | 3.98 fl oz |
| Honey | 1.42 | 2.38 fl oz |
| Butter | 0.955 | 3.54 fl oz |
Densities are approximate typical values; fl oz computed as 100 g ÷ density ÷ 29.5735 and rounded.
Common mistakes
- Assuming 1 fluid ounce of anything weighs 28.35 g — that figure is the weight ounce, and it only lines up for water-like liquids.
- Using water's density for flour or honey; flour reads about double the fluid ounces, honey about 30 percent fewer.
- Confusing fluid ounces (volume) with the ounces on a food scale (weight) — recipes use both words loosely.
- Measuring packed brown sugar or sifted flour against a density that assumes the opposite packing.
Frequently asked questions
How do I convert grams to fluid ounces?
Divide grams by the substance's density in g/mL to get milliliters, then divide by 29.5735 to get US fluid ounces. For 250 g of water: 250 ÷ 1.00 ÷ 29.5735 = 8.45 fl oz.
How many fluid ounces is 250 grams of water?
About 8.45 US fluid ounces, because water is very close to 1 gram per milliliter and one fluid ounce is 29.5735 mL. That is just over one US cup (8 fl oz).
Are fluid ounces the same as weight ounces?
No. A fluid ounce is a volume (29.5735 mL); a weight ounce is 28.3495 grams on a scale. They happen to nearly match for water, which is why the two get mixed up for everything else.
Why does flour convert so differently than honey?
Density. Flour is a powder full of air at about 0.53 g/mL, while honey is a dense syrup at about 1.42 g/mL. The same 100 g is 6.38 fl oz of flour but only 2.38 fl oz of honey.