Fluid ounces to cups (fl oz to cup) converter

What is a fluid ounces to cups converter?

A fluid ounces to cups converter is an online tool that turns a volume expressed in fluid ounces into its equivalent in cups, and back again. Both units are common in cooking and beverage measurements, but they belong to different scales and even differ between regions, which makes a quick converter handy whenever you follow a recipe written for a different country. Enter a value on either side and the matching figure appears instantly, so you never have to do the arithmetic by hand.

Fluid ounces and cups

There are two fluid ounces in everyday use. The US fluid ounce (fl oz US) measures about 29.5735 mL, while the UK (imperial) fluid ounce (fl oz UK) measures about 28.4131 mL.

Cups come in three flavours. The US cup holds 236.588 mL, the metric cup is a round 250 mL, and the imperial cup is 284.131 mL. Because the US cup is defined as exactly 8 US fluid ounces, that pairing gives the cleanest numbers and is the default in this converter.

How does the converter work?

Internally every unit is first expressed in a common base (cubic meters), then re-expressed in the unit you asked for. In practice this means you can mix and match: convert US fluid ounces to a metric cup, or UK fluid ounces to an imperial cup, and the tool always uses the correct factor for the exact pair you selected. Pick the source unit and the target unit first, then type your number — switching a unit after typing will reinterpret the value you already entered.

Formula for conversion

To convert US fluid ounces to US cups, divide by 8 (or multiply by 0.125):

$\text{US cups} = \text{fl oz (US)} \times 0.125$

To go the other way, from US cups to US fluid ounces:

$\text{fl oz (US)} = \text{US cups} \times 8$

For UK fluid ounces to imperial cups, divide by 10:

$\text{imperial cups} = \text{fl oz (UK)} \times 0.1$

And from imperial cups back to UK fluid ounces:

$\text{fl oz (UK)} = \text{imperial cups} \times 10$

Conversion table

The table below lists common US fluid ounce amounts alongside their equivalents in US, metric and imperial cups.

Examples

Example 1: US fluid ounces to US cups

Convert 8 US fluid ounces to US cups. Since 8 US fluid ounces define exactly one US cup:

$8 \text{ fl oz (US)} \times 0.125 = 1 \text{ US cup}$

Example 2: US cups to US fluid ounces

Going the other direction, a single US cup contains:

$1 \text{ US cup} \times 8 = 8 \text{ fl oz (US)}$

Example 3: A larger batch

A recipe calls for 16 US fluid ounces of stock. In US cups that is:

$16 \text{ fl oz (US)} \times 0.125 = 2 \text{ US cups}$

Example 4: UK fluid ounces to imperial cups

In the UK system, 10 fluid ounces make one imperial cup:

$10 \text{ fl oz (UK)} \times 0.1 = 1 \text{ imperial cup}$

Notes

• The US cup is defined as exactly 8 US fluid ounces, so that conversion is precise rather than approximate.
• Mixing systems is the most common source of error: an imperial cup (284 mL) is noticeably larger than a US cup (236 mL).
• A metric cup is exactly 250 mL, which is why it does not line up with a whole number of fluid ounces.
• Always select your source and target units before entering a value, otherwise the figure you typed will be reconverted.

Frequently asked questions

How many fluid ounces are in a cup?

A US cup holds exactly 8 US fluid ounces. An imperial cup holds 10 UK fluid ounces, and a metric cup of 250 mL is roughly 8.45 US fluid ounces.

How many cups is 16 fluid ounces?

Sixteen US fluid ounces equal 2 US cups, because each US cup is 8 fluid ounces.

Is a US cup the same as a metric cup?

No. A US cup is 236.588 mL while a metric cup is exactly 250 mL, so a metric cup is slightly larger. The converter applies the correct factor for whichever cup you choose.

What is the difference between US and UK fluid ounces?

A US fluid ounce is about 29.5735 mL and a UK (imperial) fluid ounce is about 28.4131 mL, so the UK ounce is a little smaller. Be sure to pick the matching ounce type for an accurate result.

Can I convert fractions of a fluid ounce?

Yes. The converter accepts any decimal value, so half an ounce, a quarter cup or any other fractional amount converts just as accurately as whole numbers.

Why does my conversion look slightly off?

Double-check that the source and target units match what your recipe intends — a US cup and an imperial cup differ by about 20 percent, which is enough to change a result noticeably.