Example 1
- Direction: US cups to fluid ounces
- 1 cup
8 fl oz
How many fl oz is 1 US cup? 8 fl oz.
Cups to Ounces
The calculator converts US cups to fluid ounces. One US cup is 8 fl oz. Two cups are 16 fl oz. This is not a mass ounce and not a 250 ml glass.
The other page, ounces to cups, is on ounces to cups. A 250 ml glass: cup to grams.
Result
Enter a volume in US cups or in fluid ounces. The result will appear here.
How it works
The calculator multiplies US cups by 8. 1 cup is 8 fl oz. 2 cups are 16 fl oz. Half a cup is 4 fl oz.
The other way, you divide fluid ounces by 8. 8 fl oz is 1 US cup.
This is a fluid ounce, not a mass ounce. A mass ounce is on the grams and ounces page.
A 250 ml kitchen glass is not this cup. 250 ml belongs on the cup-to-grams page.
You may enter zero; the result is then also zero. The calculator does not accept negative numbers.
A comma and a period give the same fraction. 1.5 cups are 12 fl oz.
Formula
fl oz = cups × 8; cups = fl oz / 8
A US cup is 8 fluid ounces. That is the definition, not an estimate.
How to use
- Choose US cups to fluid ounces.
- Enter 1. The result is 8 fl oz.
- Enter 2. The result is 16 fl oz.
- The other way, enter 8. The result is 1 US cup.
1 US cup is 8 fl oz
A US cup holds 8 fluid ounces. 2 cups are 16 fl oz.
- US cup
- 8 fluid ounces. This is not a 250 ml glass.
- fl oz
- US fluid ounce. 1 cup = 8 fl oz.
- 8
- The US cup constant. Not a rounding.
Examples
Example 2
- Direction: US cups to fluid ounces
- 2 cups
16 fl oz
How many fl oz are 2 US cups? 16 fl oz.
Example 3
- Direction: US cups to fluid ounces
- 0.5 cup
4 fl oz
How many fl oz is half a US cup? 4 fl oz.
Related calculators
Frequently asked questions
How many fl oz is 1 US cup?
8 fl oz. A US cup is 8 fluid ounces.
How many fl oz are 2 US cups?
16 fl oz. Two times 8.
How many fl oz is half a cup?
4 fl oz.
Is this a mass ounce?
No. A mass ounce is on the grams and ounces page. This page uses the fluid ounce.
Is this a 250 ml glass?
No. A 250 ml glass is on the cup-to-grams page. Here a US cup is 8 fl oz.
Can volume be negative?
No. Zero is allowed; after conversion the result is still zero.
Is 1.5 cups 12 fl oz?
Yes. One and a half times 8 is 12.
Where do I convert millilitres?
On the fl oz to ml page. That page has no cup field.
Do a comma and a period both work?
Yes. 1,5 and 1.5 give the same fraction.
Where do I convert ounces to cups?
On the ounces to cups page. That page starts from ounces.
Sources
A US cup is 8 fluid ounces.
Page updated in 2026.