🧪 fl oz to cup — Fluid Ounce to US Cup Converter

Convert volume units — liters, gallons, cups, milliliters, cubic meters, pints, quarts.

1 unit =
From
To
Formula 1 fl oz = 0.125 cup
UnitNameValue
L Liter 0.0295735
mL Milliliter 29.5735
Cubic Meter 0.0000295735
gal(US) US Gallon 0.0078124959
gal(UK) UK Gallon 0.0065052606
qt US Quart 0.031249967
pt US Pint 0.0625
cup US Cup 0.125
Last updated: March 2026

Fluid Ounce to US Cup Conversion Table

Common fluid ounce values converted to us cup — factor: 1 fl oz = 0.125 cup

Fluid Ounce (fl oz)US Cup (cup)Context
0.5 fl oz0.0625 cupHalf ounce
1 fl oz0.125 cupShot
2 fl oz0.25 cupDouble shot
4 fl oz0.5 cupHalf cup
6 fl oz0.75 cupOne cup
8 fl oz1 cupOne cup
12 fl oz1.5 cupSoda can
16 fl oz2 cupOne pint
20 fl oz2.5 cupLarge cup
32 fl oz4 cupOne quart
64 fl oz8 cupHalf gallon
128 fl oz16 cupOne gallon
256 fl oz32 cup2 gallons
512 fl oz64 cup4 gallons
1,024 fl oz128 cup8 gallons

About Fluid Ounce to US Cup Conversion

Converting fluid ounce to us cup comes up frequently in cooking, chemistry, medicine, and engineering. A recipe written in metric units may need to be adapted for a kitchen using us cup, or a laboratory protocol may specify volumes in fluid ounce that need to be measured with equipment calibrated in us cup.

In everyday use, knowing that 5 fl oz = 0.625 cup and 10 fl oz = 1.25 cup covers most common situations. For bulk calculations, 100 fl oz = 12.5 cup is a useful anchor. The reverse conversion — us cup back to fluid ounce — uses the factor 8, so 1 cup = 8 fl oz.

All conversions use the internationally recognized factor of exactly 1 fl oz = 0.125 cup. Calculations are performed in IEEE 754 double-precision floating point, giving accuracy to at least 8 significant figures — more than sufficient for any practical application.

Quick Answer

Formula: US Cup = Fluid Ounce × 0.125

Multiply any fluid ounce value by 0.125 to get us cup. One fluid ounce equals 0.125 cup.

Reverse: Fluid Ounce = US Cup × 8

Worked Examples

One US cup
8 fl oz × 0.125 = 1 cup
8 fl oz = 1 US cup.
One fluid ounce
1 fl oz × 0.125 = 0.125 cup
1 fl oz = 0.125 cups.
One US quart
32 fl oz × 0.125 = 4 cup
32 fl oz = 4 cups = 1 quart.
One US gallon
128 fl oz × 0.125 = 16 cup
128 fl oz = 16 cups = 1 gallon.

Mental Math Tricks

÷ 8 exactly

Fluid ounces ÷ 8 = cups. Eight fl oz = one cup.

Key anchors

16 fl oz = 2 cups = 1 pint. 32 fl oz = 4 cups = 1 quart.

Reverse

Cups × 8 = fl oz.

Who Uses This Conversion?

Beverage Formulator

Labels product nutrition facts and serving sizes in fluid ounces as required by FDA.

Bartender

Measures spirit pours and mixers in fl oz using jiggers for cocktail consistency.

Convenience Store Manager

Tracks soda fountain syrup and cup sizes (12, 16, 20, 32 fl oz) for inventory.

Packaging Engineer

Designs bottle fill levels in fluid ounces for US retail compliance.

Pediatrician

Recommends daily fluid intake for children in fluid ounces by age group.

Savvy Shopper

Compares unit prices per fluid ounce on beverage labels to find the best value.

Frequently Asked Questions

About Fluid Ounce and US Cup

Fluid Ounce (fl oz)

The US fluid ounce is defined as 1/128 of a US gallon, exactly 29.5735 mL. The US and UK fl oz differ: the US is 29.57 mL while the Imperial fl oz is 28.41 mL.

Fluid ounces appear on every US beverage container: a soda can is 12 fl oz, a water bottle is 16.9 fl oz, and a US shot glass is 1.5 fl oz.

Interesting fact: Despite sharing the name 'ounce', the fluid ounce measures volume, not weight. One fl oz of water weighs about 1.04 oz, but one fl oz of honey weighs about 1.5 oz.

US Cup (cup)

The US customary cup is defined as exactly 8 US fluid ounces, or 236.588 mL. It was standardized by Fannie Farmer in her 1896 cookbook The Boston Cooking-School Cook Book.

The cup is the backbone of US baking: nearly every American recipe uses cup measurements for flour, sugar, butter, and liquids. Standard sets include 1 cup, ½ cup, ⅓ cup, and ¼ cup.

Interesting fact: Australia uses a metric cup of 250 mL, slightly larger than the US cup, which can cause recipe confusion in international cooking.