What Is the Imperial System?
The imperial measurement system, or the British Imperial system, is a traditional system of measurements based on the old English units.
(The English units, consisting of Winchester units and Exchequer Standards, were the prevailing system before 1826. This system was subsequently replaced by the Imperial and US customary systems that were developed later.)
The imperial system of units was first defined in the British Weights and Measures Act 1824 and developed through various Acts and amendments. It replaced the Winchester Standards that had been in practice since 1588 and became official in 1826. Although most nations adopted the metric system by the late 20th century, some parts of the world still use imperial units.
Other Systems of Measurement
 The United States uses the system with the Customary units of measurement, which also originated from the old English system. Thus, the customary and Imperial systems are quite similar, with distinct differences in terms of some conversion factors and interpretations of units.
 The metric system is the measurement system that is used worldwide. The SI system (The International System of Units), commonly known as the modern form of the metric system, is the international standard for measurement. It is closely related to the metric system and is constantly updated to make it the global standard.
What Are the Different Units of Measurement in the Imperial System?
The different units of measurement in the Imperial system are known as Imperial units. The following Imperial system chart includes a list of Imperial units of measurement.
Length  Weight  Volume (liquid and dry)  Area  Volume 






Conversion Between Imperial Units
Length  Weight  Volume  Area 





Imperial System and Customary System
Imperial System  Customary System 
It was implemented in the United Kingdom, its territories, and former colonies. It’s still prevalent in everyday use.  It is used in the United States of America. 
1 Imperial fluid ounce ≈ 28.4131 milliliters  1 US fluid ounce ≈ 29.5735 ml 
1 Imperial pint = 568.261 milliliters = 20 imperial fluid ounces  1 US pint = 473.176 ml = 16 US fluid ounces 
1 Imperial quart = 1.13 liters = 40 fluid ounces  1 US quart = 0.94 l = 32 US fluid ounces 
1 Imperial gallon = 4.54 liters = 160 fluid ounces  1 US gallon = 3.78 liters = 128 fluid ounces 
Metric Units of Measurement?
The metric system is a decimalbased system of measurement. It is used worldwide in scientific calculations and research. The base units for length, weight (mass), and capacity (volume) in the metric system are meter, gram, and liter, respectively.
Different units in the metric system are:
 Length: Meter (m), Kilometer (km), Hectometer (hm), Decameter (dam), Decimeter (dm), Centimeter (cm), Millimeter (mm), etc.
 Weight: Gram (g), Kilogram (kg), Milligram (mg), etc.
 Capacity: Milliliter (mL or ml), Liter (L or l), etc.
Is the Imperial System Still in Use?
 In the United Kingdom, metric units are officially used, but Imperial units are still found in everyday transactions among the general population.
 The United States, the customary system or the US standard system is officially used (which is similar to the Imperial system except for the volume measurements). Despite initial intentions to adopt the metric system, the United States continues to use the Imperial system.
 In many parts of the government in Libya and Myanmar, the Imperial system is prevalent. In contrast, other parts have started using the SI system.
Easy Conversions Between Imperial and Metric Units
The table shows the different conversions between metric and imperial units.
Length  Mass  Volume/Capacity 




Facts about Imperial System
 The British Imperial System was established as a unified measurement system for use in the United Kingdom and Commonwealth nations.
 One notable advantage of the imperial system is it is based on human body measurements, with units like the inch representing the length of a thumb and the foot the length of a foot.
Conclusion
In this article, we have learned about the imperial system and the conversions between imperial and metric systems. Now, let’s solve some examples and practice problems to understand the conversions better.
Solved Examples on Imperial System
Example 1: Change the following lengths into inches.
i) 4 feet
ii) 7 yards
iii) 3 miles
Solution:
i) 4 feet
1 foot = 12 inches
Thus, 4 feet = 4 × 12 = 48 inches
ii) 7 yards
1 yard = 3 ft = 36 inches
7 yards = 7 × 36 inches = 252 inches
iii) 3 miles
1 mile = 1760 yards = 1760 × 36 inches = 63,360 inches
Thus, 3 miles = 63,360 × 3 inches = 190,080 inches
Example 2: Convert the following length measurements into centimeters.
i) 6 inches
ii) 8 feet
iii) 4 yards
Solution:
i) 6 inches:
1 inch = 2.5 cm
Thus, 6 inches = 6 × 2.5 cm = 15 cm
ii) 8 feet
1 foot = 12 inches.
Thus, 8 feet = 8 × 12 inches = 96 inches
Now, 1 inch = 2.5 cm
Thus, 96 inches = 96 × 2.5 cm = 240 cm
iii) 4 yards:
1 yard = 3 feet
Thus, 4 yards = 4 × 3 feet = 12 feet
1 foot = 12 inches
Thus, 12 feet = 12 × 12 inches = 144 inches
Now, 1 inch = 2.5 cm
Thus, 144 inches = 144 × 2.5 cm = 360 inches
Example 3: Convert 5 imperial gallons into liters.
Solution:
1 imperial gallon = 4.54609 liters
5 imperial gallons = 5 × 4.54609 liters
5 imperial gallons = 22.7304 liters
Practice Problems on Imperial System
Imperial System  Definitions, Unit Conversions, & Examples
The United States of America uses the _______ system of measurement.
The United States of America uses the Customary system of measurement.
What is the largest volume? 1 imperial pint, 1 liter, 2,500 mL, or 1 imperial gallon?
1 imperial pint = 0.568261 liters
2,500 mL = 2.5 liters
1 imperial gallon = 8 imperial pints = 4.54609 liters
Thus, 1 gallon is the largest volume.
Which is bigger? A metric ton (tonne) or an Imperial ton?
1 metric ton = 1 tonne = 1,000 kg
1 imperial ton = 1,016.05 kg
Thus, 1 ton > 1 tonne
Frequently Asked Questions about Imperial System
Do US schools teach the metric measurements?
The United States uses the Customary System of Measurement established during the Industrial Revolution. While the metric system is taught in schools, a formal switch has yet to be made.
Which is simple? Metric system or imperial system?
The metric system is preferred for its simplicity and consistency, especially in calculations and scientific applications. It is based on the decimal system. So, all conversions within the system involve just moving the decimal point.
How does “the metric system” and the SI differ?
The metric system and the International System of Units (SI) are often used interchangeably or in informal contexts, but the SI system is a more standardized, precise, and modern form of the metric system. It is used worldwide for scientific and research purposes.