How Many Ounces, Quarts And Liters In a Gallon?

You’ve probably heard people debating whether it’s good to drink half a gallon or a full gallon of water every day to keep the body healthy. Have you ever wondered how much is a gallon? How to convert ounces, liters or quarts to gallons? This article will help you get a clear understanding on this topic.

So how many ounces, liters, and quarts in a gallon? It depends on the region where you live. In the US, one fluid gallon equals 128 fluid ounce or 3.79 liters. One dry gallon equals 148.94 oz. In the UK, one gallon equals 160 imperial ounce or 4.55 liters.  Although imperial gallons are no longer the official measure for volume, many people still use it. As far quarts and gallons, it’s pretty easy to remember a quart is one-quarter of a gallon.

This post will help you with conversions and some basic calculations. Besides this, when researching this topic, I’ve also found some interesting history behind the imperial and US measuring systems. So read on!

Ounce And Gallon

What is A Gallon?

A gallon is a measure of unit capacity in English-speaking countries. The abbreviation is “gal”. The US liquid gallon is simply called gallon, however, there are two other gallons out there: imperial gallon and dry gallon also known as corn gallon or grain gallon, which is mostly used in agriculture to measure the grain and other dry commodities.

The U.S. liquid gallon is exactly 3.785411784 liters, and the U.S. dry gallon is equal to 4.4048838 liters. An imperial gallon is approximately 1.2 US gallons, which means an American gallon is smaller. An imperial gallon is defined as 4.54609 liters, which is used in the United Kingdom, Canada, and some Caribbean nations. The US gallons are used in some Latin American and Caribbean countries. 

How to Convert Gallons to Ounces? 

First, you need to know what type of gallons needed to be converted. To convert from gallons to oz, multiply the number of gallons “x” by 128 for US fluid gallon, 148.94 for US dry gallon, and 160 for the imperial (UK) gallon.

For example, to convert 5 fluid gallons to ounces, multiply 5 by 128; to convert 5 US dry gallons to ounces, multiply 5 by 148.94; to convert 5 imperial gallons to ounces, multiply 5 by 160.

It’s worth noting that even though ounces and fluid ounces share a similar name, they are quite different. Ounces are used to measure the weight of dry ingredients, such as flour, sugar, and beans. It can also be used for yogurt or honey. Ounces are most commonly used in recipes, especially baking. Measuring the weight of dry ingredients on a scale in ounces is more accurate compared to using measuring cups. 

On the other hand, fluid ounces (abbr. “fl oz”) are a measurement for volume or space something takes up. It applies to liquid such as water or milk. Weight and volume are totally different. Think about one cup of flour and one cup of milk. They both have the same volume, but they weight differently. Water is the only exception here because one cup of water happens to equal both 8 fluid oz in volume and 8 oz in weight. 

Here is a quick reference list between US Gallon and Imperial Gallon:

1 US Fluid Gallon = 128 US Fluid oz

1 US Dry Gallon = 148.94 US Fluid oz

1 Imperial Gallon (UK) = 160 Imperial Fluid oz (UK)

1 Imperial Gallon = 1.2 US Fluid Gallon

1 Imperial Gallon = 1.03 US Dry Gallon

1 US Fluid Gallon = 0.83 Imperial Gallon

1 US Fluid Gallon = 0.86 US Dry Gallon

1 US Dry Gallon = 0.97 Imperial Gallon

1 US Dry Gallon = 1.16 US Fluid Gallon

This is a conversion table between gallons and ounces. 

Gallons (US)Gallons (UK)Ounces (US)Ounces (UK)

Quart and Gallon

What Is A Quart?

A quart is a unit of liquid capacity equal to 32 fluid ounces or a quarter of a gallon. It is widely used in the US, Australia, and some other countries. An example of a quart is a container of berries sold at the supermarket. If you have an 8-ounce water bottle, you need to drink four of them to make it a quart. The US quart is equivalent to 0.946 liters.

When we talk about gallons in this post, we mentioned there is the imperial gallon, dry gallon, and liquid gallon.  Similarly, there is the imperial quart (in the British imperial system) and there is both a dry quart and a liquid quart in the US customary system of measurement. The British imperial measurement system has different standards for units like cups, pints, quarts, gallons, inches, and feet.

Gallon is a liquid measure unit accepted in many countries. The US liquid gallon equals approximately 3.785 liters. Quart (qt or qrt) is a unit of liquid measure widely used in the USA, Australia, and some other countries. The US quart is equivalent to 0.946 liters.


Using Quarts and Gallons

Quarts and gallons are the most common measurements for selling different fluids. For example, petrol is usually dispensed by gallons, and milk is sold in gallon or quart containers. Smaller liquid measures are used not so often though one can still buy a pint of juice in any grocery store.

These units can also be used in cooking, but as a rule, it is more convenient to measure liquids in pints, fluid ounces, cups, tablespoons, and teaspoons. The following table will help you to convert these units. 

teaspoontablespoonfluid ozcupspints quarts
one US gallon7682561281684
one US quart1926432421

Liters And Gallons

A liter is a metric unit used to measure liquid volume both in the US and imperial system. One liter is about 4 cups of water (1 cup being approximately 250 ml). You may also find a 1-liter bottle of ketchup in the grocery store. One liter of water weighs exactly one kilogram.

Here are the conversion equations between liters and gallons:

1 Gallon [Fluid, US] = 3.7854118 Liters
1 Gallon [Dry, US] = 4.4048838 Liters
1 Gallon [UK] = 4.54609 Liters

US GallonLiters
LitersUS Gallon

Why is US Gallon Different than an Imperial Gallon?

The imperial and United States customary systems of measurement share the same heritage dated back to the English systems used in the Middle Ages. Think of different dialects in the same language. British people and American colonialists used to have the same measuring system when they lived together. They had used the Queen Anne’s gallon of 3.785 L to measure wine. They also had different volumes and names to measure both beer and grain. A gallon of wine and a gallon of ale were different sizes.

In 1824, the need for standardization became obvious. The Weights and Measures Act of 1824 set up the imperial system. They chose a single imperial term and lumped together all three measurements. By picking a roughly-average volume, they started to call it a gallon, which is based on 10 pounds or 277.42 cubic inches of water. They also took the opportunity to remove an excess gallon and the old ale gallon became the gallon in the UK. 

American still stuck to tradition and kept just the Queen Anne’s volume for their own gallon definition. The standard US gallon would be the “Queen Anne” wine gallon, of 231 cubic inches (3.785 liters). The dry gallon was used in the US for grain and other dry goods, being 268.8025 cubic inches. 

The difference between the American and Imperial gallon is about 20 percent. The US gallon is 83.3 percent of the Imperial gallon; the imperial gallon is about 20% greater in volume than the US gallon. This has always led to confusion. By the time they realized how annoying the difference between these two systems, it was too late to change it. In 1959 the US, UK, Canada, Australia, and other English speaking countries agreed to use the same definition of the yard and pound, but what about gallon? Not fixed. 

In both the US and UK, it is legal to sell liquids by the liter instead of the gallon and be assured of getting the same size all over the world.

Related Questions:

1. How many 16 oz make a gallon?

1 gallon of water, for example, equals 8 16-oz bottles. How to calculate? 1 US gallon equals 128 ounces. So you simply divide 128 by 16. The answer is 8. 

2. How many 32 oz cups make a gallon?

1 US gallon is 128 ounces, which is 4 times the 32-oz cups. Simply divide 128 by 32, and you get the answer 4. 

3. Is 64 oz half a gallon?

1 US gallon is 128 ounces. If you divide 128 by 64, you’ll get the answer 2. A gallon has 2 64 oz. In other words, 64 oz is half a gallon. 

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