How much does 8 fluid ounces weigh?

When it comes to cooking, baking, or any measurement that involves liquids, it’s important to have a solid understanding of fluid ounces and how they convert to other units of measurement. Specifically, many recipes will list ingredient amounts in fluid ounces, so knowing how much 8 fluid ounces equates to by weight can ensure you use the right quantities.

What is a Fluid Ounce?

A fluid ounce is a unit of volume used in both the US customary system as well as the British imperial system. It is used to measure the volume of liquids. The US fluid ounce is defined as 1⁄128 of a US gallon, while the imperial fluid ounce is defined as 1⁄160 of an imperial gallon.

One fluid ounce is equal to:

  • 29.5735 milliliters
  • 1.8046875 cubic inches
  • 1⁄128 of a US gallon
  • 1⁄160 of an imperial gallon

The fluid ounce is distinct from the ounce as a unit of weight. While they share the same name, these are two different units. Weight ounces are a measure of mass, while fluid ounces are a measure of volume.

How Much Does 1 Fluid Ounce Weigh?

While fluid ounces measure volume, they can be converted to a weight in ounces or other units like grams. However, the weight of 1 fluid ounce depends entirely on the density of the liquid being measured. The density of water is 1 gram per milliliter, which equates to 0.03381402 ounces per fluid ounce. So for water, 1 fluid ounce weighs exactly 1 ounce.

For other liquids, the weight of 1 fluid ounce is calculated by:

Weight (oz) = Fluid ounces x Density of liquid (oz/fl oz)

For example:

  • 1 fl oz of water weighs 1 oz
  • 1 fl oz of whole milk (density 1.03 oz/fl oz) weighs 1.03 oz
  • 1 fl oz of olive oil (density 0.92 oz/fl oz) weighs 0.92 oz

So the weight of 1 fluid ounce depends on the type of liquid being measured. Water is an easy baseline at 1 fluid ounce = 1 ounce. Heavier liquids like milk will make 1 fluid ounce weigh slightly more, while lighter liquids like oil will make 1 fluid ounce weigh slightly less.

Converting Between Fluid Ounces and Weight

Since fluid ounces are volume and weight ounces are mass, you need to know the density of the liquid to convert between the two units. Here are some common conversion factors:

  • 1 fluid ounce of water = 1 ounce by weight
  • 16 fluid ounces of water = 1 pound
  • 1 fluid ounce of whole milk = 1.03 ounces by weight
  • 1 fluid ounce of olive oil = 0.92 ounces by weight

To convert between fluid ounces and grams, you need to know that 1 milliliter of water weighs 1 gram. Using the density in grams per milliliter, you can calculate:

  • 1 fluid ounce of water = 29.57 mL x 1 g/mL = 29.57 grams
  • 1 fluid ounce of whole milk = 29.57 mL x 1.03 g/mL = 30.46 grams
  • 1 fluid ounce of olive oil = 29.57 mL x 0.92 g/mL = 27.22 grams

How Much Does 8 Fluid Ounces Weigh?

Now that we know how to convert 1 fluid ounce to a weight, we can calculate how much 8 fluid ounces weighs:

Liquid Weight of 8 Fluid Ounces
Water 8 ounces
Whole milk 8.24 ounces
Olive oil 7.36 ounces

To summarize:

  • 8 fluid ounces of water weighs 8 ounces
  • 8 fluid ounces of whole milk weighs about 8.24 ounces
  • 8 fluid ounces of olive oil weighs about 7.36 ounces

And in grams:

  • 8 fluid ounces of water weighs 236.56 grams
  • 8 fluid ounces of whole milk weighs 243.68 grams
  • 8 fluid ounces of olive oil weighs 217.76 grams

So while 8 fluid ounces is a standard volume measurement, its weight in ounces or grams depends on the density of the liquid being measured. For water, the simplest conversion is that 8 fluid ounces = 8 ounces in weight. For other liquids, you need to multiply the density of that liquid by 8 fluid ounces to get the equivalent weight.

Common Uses for 8 Fluid Ounce Measurements

Knowing the weight of 8 fluid ounces is useful for recipes and other situations that call for precise liquid measurements by volume. Here are some of the most common uses for an 8 fluid ounce measurement:

  • Beverage servings – Many sodas, juices, and other drinks are sold in 8 fluid ounce individual serving sizes.
  • Measuring cups – Most measuring cups for cooking have 8 fluid ounce gradations to standardize ingredients for recipes.
  • Nutritional information – Nutrition facts labels will often list nutrient content per 8 fluid ounces for beverages.
  • Infant feeding – Baby bottles are commonly 4-8 ounces for an appropriate serving size.
  • Liquid medicines – Cough syrups, elixirs, and other liquid medications may be dosed by 8 fluid ounce amounts.
  • Cocktail recipes – Some mixed drink recipes call for 1-2 ounces of various alcoholic ingredients totaling around 8 ounces.

Knowing that 8 fluid ounces weighs right around 236 grams or 8 ounces by weight can help with precisely following recipes, measuring proper servings sizes, or any situation where volume and weight need to be inter-converted.

Tips for Measuring 8 Fluid Ounces

Here are some useful tips for working with an 8 fluid ounce volume measurement in cooking, baking, mixology or anything else:

  • Use a liquid measuring cup with ounce markings – This is the easiest way to directly measure out 8 fluid ounces.
  • Opt for a clear glass or plastic cup – You’ll get the most accurate meniscus reading.
  • Set the cup on a level surface and read at eye level – This helps get an accurate volume measurement.
  • For small amounts, use a shot glass or jigger – These bartending tools are designed for 1.5 ounce and 1 ounce pours.
  • Weigh with a kitchen scale for sticky ingredients like honey – Density matters more when viscosity varies.
  • Calculate from milliliters for metrics – 29.57 milliliters = 1 fluid ounce, so 8 ounces is 236.56 mL.

Getting an accurate 8 fluid ounce measurement is important for both volume and determining the weight. Follow these tips for the best precision whether you’re mixing cocktails, baking cakes, or whipping up any other recipes requiring liquids.

Common Conversions and Equivalents for 8 Fluid Ounces

Here is a summary of some of the most helpful conversions for dealing with 8 fluid ounces:

  • 8 fluid ounces = 1 cup (precisely, 8.11574 fluid ounces per US cup)
  • 8 fluid ounces = 0.5 pint (16 fl oz per US pint)
  • 8 fluid ounces = 0.0625 gallon (128 fl oz per gallon)
  • 8 fluid ounces = 236.588 milliliters (29.5735 mL per fluid ounce)
  • 8 fluid ounces of water weighs about 8 ounces
  • 8 fluid ounces of water weighs about 236.56 grams (water density is 1 g/mL)

No matter what units you need to work in, this summary gives you the key conversions to and from 8 fluid ounces. Keep these handy for any recipe or measurement involving liquids!

Frequently Asked Questions

Why don’t fluid ounces and weight ounces align?

This is because fluid ounces measure volume, while ounces by weight measure mass. Volume depends on the space a liquid takes up, while mass or weight depends on how much matter is in an object. For water they align at 1 fluid ounce = 1 ounce. But for other liquids they differ based on density.

Can I use ounces and fluid ounces interchangeably?

No, ounces and fluid ounces are different units and cannot be used interchangeably. Ounces measure weight or mass. Fluid ounces measure volume of liquids. The only time they are equal is for pure water, which has a density of 1 ounce per fluid ounce. Other liquids like milk or oil will weigh slightly more or less than their volume in fluid ounces.

How can I easily convert fluid ounces to grams?

Since 1 milliliter of water = 1 gram, you can convert fluid ounces to grams by:
Grams = Fluid ounces x 29.5735 mL/fl oz x Density of liquid (g/mL)

For water density is 1 g/mL, so 8 fl oz of water is 8 x 29.5735 x 1 = 236.56 grams. For liquids with other densities, adjust the density factor accordingly.

Why are fluid ounces used for liquids but regular ounces are used for solids?

This convention originated because the fluid ounce was defined based on volumes of liquid measurement, while the ounce was defined historically based on weights of key commodities. Using fluid ounces for liquids and regular ounces for solids became standard practice to distinguish the concepts of volume vs. mass.

Are ounces by volume and ounces by weight exactly the same for water?

Yes, for water the units align exactly because water has a density of 1 gram per milliliter. So 1 fluid ounce of water weighs 1 ounce, since 29.57 mL weighs 29.57 grams. This unique property of water makes the ounce-to-ounce conversion work, unlike any other liquid.


In summary, 8 fluid ounces is a set volume measurement that equates to different weights depending on the density of the liquid being measured. For water, 8 fluid ounces weighs exactly 8 ounces. For other liquids, you need to multiply the density by 8 fluid ounces to get the weight. Understanding fluid ounce to ounce and fluid ounce to gram conversions allows you to translate liquid volumes into weights for recipes, measurements, and other uses where density and mass matter. Use this guide for handy conversion factors and tips for working with 8 fluid ounces of any liquid.

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