How Much Does a 5-Gallon Bottle of Water Weigh?

Believe it or not, most of the world won’t know what you mean if you use gallons to describe the volume of a water bottle.

This is because most of the world uses SI (the International System of Units), aka the metric system. Luckily for us, we know what we mean by a 5-gallon bottle, so we can go ahead and ask the question.

What’s the weight of a 5-gallon bottle of water? Well, this is largely dependent on the kind of gallon you’re using.

An imperial gallon contains 160 fl. oz. (fluid ounces), and a 5-imperial gallon bottle of water weighs fifty pounds (disregarding the weight of the bottle itself).

A US gallon contains 128 fl. oz., and a 5-US gallon bottle of water weighs 41.7 pounds, again, disregarding the weight of the bottle.

Table of Contents

What is an imperial gallon?


An imperial gallon is a unit that measures volume in the imperial units system and is a unit of measurement in the Imperial System of Britain. In Great Britain, this was the official, original system of weights and measurements used until 1965 when it was mostly replaced by the metric system.

At present, imperial units are legally defined in terms of metric units.

The Imperial System developed from the thousands of Anglo-Saxon, Celtic, Roman, and other traditional local units used in the Middle Ages. Customary names like foot, pound, and gallon were commonly employed.

However, the value they referred to varied with location, time, product, trade, and many other specifications.

The early royal standard used to ensure uniformity was given the name Winchester in honor of the 10th-century historic capital city of Britain. The Saxon King, Edgar the Peaceable, kept the royal bushel measurement and possibly others here at his palace in Winchester.

Why does the US have its own gallon?

The US measuring system was founded upon the English system, also known as imperial units. In a way, America still follows in the footsteps of Britain because, even though the British have since changed to SI, their transition into it wasn’t as effortless as they’d hoped, and imperial units remain in extensive use.

Legally, as per the 1988 laws, SI became the standard measurement system used for commerce and trade across the US. However, most consumer products and American cookbooks remain based on the US measuring system, so it is essential to know the two systems.

SI is also taught in schools. Even though young children find converting to and from metric units difficult, those going on to become scientists or doctors still need to fully learn SI. This means that US children have to be taught two measurement systems.

For the rest of this article, the word ‘gallon’ means ‘US gallon’.

A short history of weights and measures and how we got to where we are today

 Imperial gallon

As we are only concerning ourselves with liquid measurements in this article, let’s start by listing US liquid measurements. These are:

  • gallon (gal), which is made up of 4 quarts
  • quart (qt), made up of two pints
  • pint (pt), made up of 4 gills
  • gill (gi), made up of 4 fluid ounces
  • fluid ounce (fl. oz.), made up of 8 fluid drams
  • fluid dram (fl. dr.), made up of 60 minims (so now you know what a dram of whisky is)
  • minim (min), which is 1/60th of a fluid dram

Initially, the situation with weights and measures was a mess

Before 1215 and the Magna Carta, violations of weights and measurements were so frequent a clause was included in the charter to rectify the problem. Wine and grain were given a common measurement.

The following year, an ordinance of the royal court titled “Assize of Weights and Measures” established a broad set of standard units, which were so successful that it was in effect for several centuries following.

The “Iron Yard,” also known as the “standard yard,” was established for the entire kingdom. It was separated into the standard 3 feet each of 12 inches.

The golden age of Queen Elizabeth I and a leap forward in weights and measures

There was no major change over the next 200 years following the death of Queen Elizabeth I, save for a few revisions and clarifications made here and there.

The dry measure corn bushel was first defined in 1701. In 1707, the term “wine gallon” came to be described as a round measurement with an even bottom comprising a well-defined number of cubic inches.

There was also the corn gallon and a slightly older, smaller-sized wine gallon.

Numerous other attempts to standardize weights and measures failed, and it wasn’t until the turn of the century that major changes were made.

The 19th and 20th centuries saw the emergence of our modern system of weights and measures

The 1824 Weights and Measures Act was designed to remove the medieval confusion, and in it, the gallon was given a standard definition, which was reaffirmed in the Act of 1878. The 1878 act also redefined yards.

Additional units became standardized during that time too.

Then, as a result of an act of the Parliament that was passed in the year 1963, English weights and measurements were changed to conform to the metric system, with the official changeover taking place two years later.

Meanwhile, in the United States…

In his first address in 1790 to Congress, George Washington emphasized the necessity of standards in measures, weights, and currency, the latter of which was settled in decimal format. However, the immense apathy to changing of the familiar system of English measures and weights permeated commerce and industries involving tools, machines, measures, and containers.

Popular psychology stopped the decimal system from working, although it was promoted in the name of Thomas Jefferson.

In France, the metric system was becoming ever more popular, and Secretary of State John Quincy Adams, in an important address to Congress in 1821, recommended the same system. However, Congress was having none of it and refused to adopt the metric system.

How the US measures such as the gallon stayed close to the British system

Instead of embracing the metric system, the United States attempted to harmonize its system with England’s, but differences appeared. For instance, the United States still used the Queen Anne gallon, which the British had abandoned in 1824.

Under the overall supervision of the Treasury Department, the Office of Standard Weights and Measures carried out the creation of the nation’s standards. The yard’s standard imported from London earlier in the year ensured a tight relationship between the American and English yards. However, the US kept the Queen Anne gallon.

The US bushel originated from the earlier “Winchester bushel,” a standard that dates back to the 15th century. The standard was replaced by the British Act of 1824.

Thus, the US gallon and bushel are smaller by 3% and 17% compared to the British gallon and bushel and are more old-fashioned than their British counterparts.

How the US tries to standardize weights and measures across all states

In the late 19th century, the new states that joined the United States were given sets of standards. Later in the century, lobbying to increase and expand the functions of the OSWM (Office of Standard Weights and Measures), was finally successful and in 1901, Congress acted to create a new body, the National Bureau of Standards.

In 1988, the OSWM was transformed into what we now call the National Institute of Standards and Technology, a branch of the Commerce Department.

Standard Weights and Measures

One of the initial actions by the Bureau was to organize the national conference on measures and weights to establish standards for all states. An important function of the annual conference was updating the model state law regarding measures and weights, which led to a degree of uniformity in the law.

Despite these measures, the US government remains unique among other major nations by refraining from exerting control over weights and measures at the national level.

A notable distinction to this general state of disparity was the Metric Act of 1866, which decreed the use of the metric system throughout the entire United States.

How the gallon relates to the metric system’s fluid measurements

How and why the metric system emerged

A major and important effect of the French Revolution was the creation of a new system of measurements and weights based on metric units. Previously, over many years, European scientists had discussed the possibility of creating a rational and uniform system of weights and measures that could replace regional and national variations that made commercial and scientific communication difficult.

The emergence of the National Assembly following the collapse of the Bastille made it a political possibility. In 1790, the National Assembly launched an inquiry that ended in the French Academy of Sciences being ordered to write a report on the matter.

Gallons converted into the metric system

You may often hear “liter” when you’re in countries that use the SI measuring system, but surprisingly, the liter is not an SI unit. One liter = 1 cubic decimeter (dm3). Here is a list of SI volumetric units:

SI volumetric units

Prefixes and the meaning of each:

  • milli 1/1000th
  • centi 1/100th
  • deci 1/10th


  • 1 cubic centimeter (cm3) = 1 milliliter (mL)
  • 1 centiliter (cL) = 10 mL
  • 1 deciliter (dL) = 10 cL
  • 1 liter (L) = 10 dL = 1000 mL
  • If you do the sums right, you will find that 1L (1 liter) = 1 cubic meter.

1 gallon = 3.7854 liters

How the US is integrating the metric system

  • US coins & currency are created using specifications in metric units.
  • Like spirits and wine, many US products have been sold successfully using only metric measurements since the beginning of the 1980s.
  • Metric units are widely used in packages to convey the net amount, nutritional and health-related data for prescription medications, over-the-counter medicines, vitamin supplement dosage, and many other products for consumers.
  • SI units are being increasingly utilized for labeling consumer products across the US, for example, in the lighting industry.
US coins & currency

Fun facts about gallons

  • A hat with a ten-gallon capacity cannot contain ten gallons of liquid. The hat’s name is from the Spanish gallon, which translates to “plait” or “braid” and refers to the ornament on such hats.
  • The world’s largest, scalding-hot river is a perfect location to cook eggs without adding more expense to your bill. The hot springs gush out 65 gallons of boiling hot water each and every second. The river is situated in the hard-to-spell town of Deildartunguhver, Iceland.
  • The typical Olympic swimming pool can hold 660,000 gallons of water.
  • The largest-ever smoothie resulted from a project by Cabot Creamery Cooperative, which utilized 3200 bananas and plenty of yogurt and ice to create 400 gallons of yummy banana-based smoothie.
  • One of the costliest liquids is reportedly scorpion venom that sells for $39 million, give or take, per gallon!