Example 1
- 8
1 US cup
8 ÷ 8 = 1
Ounces to Cups Calculator
Enter fluid ounces. The calculator divides them by 8. Eight fl oz is 1 US cup, sixteen fl oz is 2 cups. This is not a mass ounce and not a 250 ml metric cup.
Result
Enter a volume. The result will appear here.
A mass ounce is on grams and ounces. A 250 ml metric cup is on cup to grams.
How results are calculated
fl oz16
cups2
The ounces to cups calculator converts fluid ounces to US cups. The formula is cups = fl oz / 8. Eight fl oz is 1 US cup, sixteen fl oz is 2 cups.
The other way, US cups are multiplied by 8. Two cups are 16 fl oz. Half a cup is 4 fl oz. The constant 8 is the US-cup definition.
Enter a volume and keep ounces to cups if you start from fl oz. A comma works like a period. Zero stays zero. A negative number is rejected.
This is not a mass ounce and not a 250 ml metric cup. Mass ounces belong on grams and ounces. A 250 ml metric cup belongs on cup to mass.
The neighboring cups to ounces page uses the same constant 8, but defaults to starting from US cups.
Enter 8 with ounces to cups and check 1 US cup. Then enter 16: the result is 2 cups. Then switch direction and enter 2: the result is 16 fl oz.
How to use this calculator
- Keep the direction fluid ounces to US cups.
- Enter 8. The result is 1 US cup.
- Enter 16. The result is 2 cups.
- Switch direction and enter 2. The result is 16 fl oz.
- To start from cups, open cups to ounces.
Formula
cups = fl oz / 8 · fl oz = cups × 8
US cup = 8 fl oz by definition. Volume ≥ 0.
US cup and fl oz
1 US cup = 8 fl oz. 2 cups = 16 fl oz.
- US cup
- A volume measure equal to 8 fl oz. It is not a 250 ml metric cup.
- fl oz
- US fluid ounce. Do not confuse it with a mass ounce on grams and ounces.
- 8
- US-cup definition constant: cups = fl oz / 8.
Examples
Example 2
- 16
2 US cups
16 ÷ 8 = 2
Example 3
- 2
16 fl oz
2 × 8 = 16
Related calculators
Frequently asked questions
How are fluid ounces converted to US cups?
The calculator divides fluid ounces by 8. Eight fl oz is 1 US cup. Sixteen fl oz is 2 cups. The other way, cups are multiplied by 8.
Is this a mass ounce?
No. Only the fluid ounce is converted here. Mass ounces belong on the grams and ounces page.
Is a US cup a 250 ml metric cup?
No. A US cup is 8 fl oz. A 250 ml metric cup belongs on cup to mass.
Are zero or negative volumes allowed?
Zero is allowed and stays zero. A negative volume is rejected.
Does a comma in 2.5 work?
Yes. A comma and a period are the same fraction. 2.5 cups are 20 fl oz.
Where do I start from cups instead of ounces?
On cups to ounces. There the default direction starts from US cups.
Where do I convert milliliters without a cup?
On milliliters and US fluid ounces. That page has no cup field.
What do the fields in the result panel show?
The primary result is the converted volume. Beside it you see the other side, the direction, and the ÷ 8 or × 8 constant.
Are 16 fl oz always 2 cups?
Yes. 16 divided by 8 is 2 US cups.
How is this different from a 15 ml tablespoon?
Here you count fl oz and a US cup. A 15 ml tablespoon belongs on the spoon page.
Knowledge sources
A US cup is defined as 8 fluid ounces.
Page updated October 12, 2026.