The factor, and the shortcut
A US fluid ounce is defined as 29.5735 cc, which makes one cc about 1/30th of an ounce. For a fast estimate, divide the cc by 30: 240 cc → 8 fl oz, close to the exact 8.11. Remember that cc is the far smaller unit — you need roughly 30 of them per ounce.
US and imperial fluid ounces are different sizes
This is the one thing that trips people up. A UK (imperial) fluid ounce is smaller than a US one, so the same cc figure gives a slightly larger number of UK ounces. Pick the right system before you convert.
The US ounce is about 4% larger, so 100 cc reads as 3.38 US ounces but 3.52 imperial ounces — the same volume, two different labels.
| System | mL per fl oz | 1 cc equals |
|---|---|---|
| US fluid ounce | 29.5735 mL | 0.033814 fl oz |
| Imperial (UK) fluid ounce | 28.4131 mL | 0.035195 fl oz |
Use US ounces by default. Reach for imperial only for UK, Irish or Australian recipes and references.
Common cc values
| Cubic centimeters | US fluid ounces | Everyday equivalent |
|---|---|---|
| 5 cc | 0.17 fl oz | one teaspoon |
| 15 cc | 0.51 fl oz | one tablespoon |
| 30 cc | 1.01 fl oz | a standard medicine cup |
| 240 cc | 8.11 fl oz | about one cup |
| 500 cc | 16.91 fl oz | a half-liter bottle |
| 1000 cc | 33.81 fl oz | one liter |
A fluid ounce measures volume, not weight. It only weighs about one weight-ounce for water; oil weighs less and honey more, so never swap fluid ounces for weight ounces.
Common questions
How many fluid ounces are in a cubic centimeter?
One cc is 0.033814 US fluid ounces, so it takes about 30 cc to make one fluid ounce. Going the other way, one US fluid ounce is 29.5735 cc.
Is a cubic centimeter the same as a milliliter?
Yes, exactly. 1 cc equals 1 mL by definition. Medicine and science tend to write mL, while engineering and older records use cc, but the volume is identical.
How do I convert 100 cc to fluid ounces?
Multiply by 0.033814. So 100 cc is 3.38 US fluid ounces. A quick mental version: 100 divided by 30 is about 3.3.
