UrbiTools

Fluid Ounces to Cups Converter

Convert fluid ounces to cups and back — 8 fl oz in every US cup, no mental maths. Everything runs instantly in your browser; nothing is uploaded.

Convert fluid ounces ⇄ cups

1 cups
8 fl oz = 1 cups (US cups & fluid ounces)

Formula: 8 fl oz ÷ 8 = 1 cups

How the fluid ounces to cups conversion works

The ratio is exact: cups = fl oz ÷ 8. A US cup is defined as 8 US fluid ounces, and a US fluid ounce is 29.5735 ml — so 8 × 29.5735 = 236.588 ml per cup, matching the cup definition exactly. Going the other way, fl oz = cups × 8.

Worked example: a recipe calling for 20 fl oz of stock needs 20 ÷ 8 = 2.5 cups. And 3 cups of water is 3 × 8 = 24 fl oz.

The one trap: fluid ounces vs ounces of weight. A US fluid ounce is a volume (≈ 29.57 ml); an avoirdupois ounce is a weight (28.3495 g). They only line up for water — 8 fl oz of water weighs about 8.34 oz, not 8 oz. If your recipe gives ounces of a dry ingredient, convert weight to volume with our grams to cups converter instead.

fluid ounces to cups questions

How many fluid ounces are in a cup?
8 US fluid ounces make 1 US cup (8 × 29.5735 = 236.588 ml). Note that fluid ounces (volume) and ounces of weight are different: 8 fl oz of water weighs about 8.34 oz.
How do I convert fluid ounces to cups?
Divide by 8: cups = fl oz ÷ 8. So 32 fl oz is 32 ÷ 8 = 4 cups, and 20 fl oz is 20 ÷ 8 = 2.5 cups. Type any figure above.
Is 8 oz the same as 1 cup?
For fluid ounces measuring volume, yes: 8 fl oz = 1 US cup exactly. But "8 oz" of weight is a different unit — 8 oz of flour, for instance, is about 1.8 cups, because flour is light. Check whether your recipe means weight or volume first.
How many cups is 16 fl oz?
2 cups (16 ÷ 8). Other handy figures: 4 fl oz = ½ cup, 12 fl oz = 1½ cups, 24 fl oz = 3 cups.
How do I convert cups back to fluid ounces?
Multiply by 8: fl oz = cups × 8. So 2.5 cups is 2.5 × 8 = 20 fl oz. Switch the direction above to do it.

More converters

mg to ml ConverterMilligrams to millilitres with density presets.ml to oz ConverterMillilitres to US fluid ounces and back.Liters to Gallons ConverterLitres to US or UK (imperial) gallons.Steps to km ConverterSteps to kilometres with adjustable stride length.cups to ml ConverterUS cups to millilitres and back.kg to lbs ConverterKilograms to pounds and back.Fahrenheit to Celsius ConverterFahrenheit to Celsius and back.grams to cups ConverterGrams to US cups with ingredient presets — flour, sugar, butter and more.ounces to grams ConverterOunces to grams and back — exact 28.3495 g per ounce.tablespoons to ml ConverterUS tablespoons to millilitres and back.teaspoons to ml ConverterUS teaspoons to millilitres and back.grams to tablespoons ConverterGrams to US tablespoons with ingredient presets.liters to quarts ConverterLitres to US quarts and back.cups to tablespoons ConverterUS cups to tablespoons and back — 16 tbsp per cup.tablespoons to teaspoons ConverterTablespoons to teaspoons and back — 1 tbsp = 3 tsp.pints to cups ConverterUS pints to cups and back — 1 pint = 2 cups.quarts to cups ConverterUS quarts to cups and back — 1 quart = 4 cups.grams to ml ConverterGrams to millilitres with ingredient presets.gallons to cups ConverterGallons to cups and back — 16 cups per gallon.liters to pints ConverterLitres to US or UK pints — the pint of beer and milk.teaspoons to cups ConverterTeaspoons to US cups and back — 48 tsp per cup.ml to liters ConverterMillilitres to litres and back — divide by 1,000.stone to kg ConverterStones to kilograms and back — exact 6.35029 kg per stone.

Sources & official guidance

Estimate only — check whether your recipe means fluid ounces (volume) or ounces (weight). See our disclaimer.