Understanding the differences between the metric and imperial systems is important, especially in cooking which requires precise measurements. In this article, we will discuss these differences and provide a guide on how to convert metric to imperial units, and vice versa.
Overview
The metric system and imperial system are the two main systems of measurement used worldwide. The imperial system is also known as the British or English measurement system.
The metric system is used in most countries, whereas the imperial system is used in only three countries – the United States, Liberia, and Myanmar.
The metric system is based on 10s, making it easy to convert between its units. However, the imperial system’s units have unique relationships with each other, which makes conversions slightly more complex. For instance, 1 pound is equivalent to 16 ounces.
In this article, we will discuss the details of the metric and imperial systems, their units of measurement, and how to convert imperial to metric units and metric to imperial units. The article includes multiple charts which you can save for future reference.
What is the metric system?
The metric system is an international decimal-based system of measurement that is currently used almost universally worldwide, except in the United States, Liberia, and Myanmar, which still predominantly use the imperial system.
Origin of the metric system
The metric system originated in France during the French Revolution in the 18th century. The aim was to create a simplified, rational measurement system that could be easily understood and applied universally.
The system was first introduced in 1795 and has since been refined and updated, with the latest definitions being adopted in the late 20th century. The metric system is widely used around the world, not only in cooking but also in various industrial and scientific fields.
Metric units of measurement
The metric system works on a base of 10, meaning that it uses multiples and divisions of 10. This makes it straightforward to convert between units. The units of the metric system include grams for mass, liters for volume, and meters for length.
Here are a few examples:
- 1 gram is equal to 1000 milligrams
- 1 kilogram is equal to 1000 grams
- 1 liter is equal to 1000 milliliters
- 1 kilometer is equal to 1000 meters
- 1 meter is equal to 100 centimeters
What is the imperial system?
The imperial system, also referred to as the English or British imperial system, is a system of measurement that was historically used in the British Empire.
Today, it is mainly used in only three countries – the United States, Liberia, and Myanmar. However, certain measures are still employed in the United Kingdom, Canada, and a few other countries.
Origin of the imperial system
The system incorporates a variety of units that were historically used in many different cultures, including the Roman Empire and Anglo-Saxon England.
Imperial units of measurement
Unlike the metric system, the imperial system is not based on a consistent system of 10s. Conversions between units often involve other numbers, such as 12 inches in a foot or 16 ounces in a pound.
The conversion between the units does not result in well-rounded numbers but numbers with decimals. This can make it more complicated to convert between units.
Common imperial measurements include the inch, foot, and yard for length; the ounce and pound for weight; and the fluid ounce, pint, quart, and gallon for volume. The Fahrenheit scale is used for temperature.
Here are a few examples:
- 1 tablespoon is equal to 3 teaspoons
- 1 cup is equal to 16 tablespoons
- 1 cup is equal to 8 ounces
- 1 pint is equal to 2 cups
- 1 quart is equal to 2 pints
- 1 quart is equal to 4 cups
- 1 gallon is equal to 4 quarts
- 1 gallon is equal to 8 pints
- 1 gallon is equal to 16 cups
- 1 pound is equal to 16 ounces
- 1 US cup is equal to 8 fluid ounces
- 1 US pint is equal to 16 fluid ounces
- 1 US quart is equal to 32 fluid ounces
- 1 US gallon is equal to 128 fluid ounces
- 1 Imperial gallon is equal to 153.7 fluid ounces
British imperial system vs. US customary system
The US customary measurement system has roots in the historical British imperial system, sharing many similarities. However, they also have some differences, primarily when it comes to units of volume.
The US customary system has separate units for measuring liquids and dry goods, whereas the British imperial system has only one set of units for both types of measurements.
For example, in the British imperial system, a gallon is equal to 4.54 liters, while in the US customary system, a liquid gallon is equal to 3.78 liters and a dry gallon is equal to 4.405.
Both systems’ fluid ounces also differ, with the imperial fluid ounce measuring 28.413 milliliters, and the US fluid ounce being 29.573 milliliters.
Weight conversion charts
While converting within the metric system is relatively easy, converting between different systems can be a bit complex. Here, you can find some common conversions that may be helpful.
Imperial to Metric weight conversion
The imperial system uses ounces and pounds for weight, while the metric system uses grams and kilograms. The conversion chart below includes common conversions, such as how many grams are in an ounce, kilograms in a pound, grams in a pound, or kilograms in an ounce.
- ½ ounce = 14.2 grams
- 1 ounce = 28.3495 grams
- 2 ounces = 56.7 grams
- 4 ounces = 113.4 grams
- 8 ounces = 0.5 pounds = 226.8 grams
- 12 ounces = 0.75 pounds = 340.2 grams
- 16 ounces = 1 pound = 453.59 grams = 0.4536 kilograms
- 20 ounces = 1.25 pounds = 566.99 grams = 0.567 kilograms
- 24 ounces = 1.5 pounds = 680.39 grams = 0.6804 kilograms
- 32 ounces = 2 pounds = 907.19 grams = 0.9072 kilograms
- 40 ounces = 2.5 pounds = 1133.98 grams = 1.134 kilograms
- 48 ounces = 3 pounds = 1360.78 grams = 1.361 kilograms
- 56 ounces = 3.5 pounds = 1587.57 grams = 1.588 kilograms
- 64 ounces = 4 pounds = 1814.37 grams = 1.814 kilograms
- 128 ounces = 8 pounds = 3628.74 grams = 3.629 kilograms
Metric to Imperial weight conversion
The chart below will make it easy for you to convert grams to ounces, grams to pounds, or kilograms to pounds.
- 14 grams = 0.494 ounces = 0.031 pounds
- 28 grams = 0.988 ounces = 0.062 pounds
- 50 grams = 1.764 ounces = 0.11 pounds
- 75 grams = 2.646 ounces = 0.165 pounds
- 100 grams = 3.527 ounces = 0.22 pounds
- 150 grams = 5.291 ounces = 0.33 pounds
- 200 grams = 7.055 ounces = 0.441 pounds
- 250 grams = 8.818 ounces = 0.551 pounds
- 500 grams = 17.637 ounces = 1.102 pounds
- 750 grams = 26.456 ounces = 1.653 pounds
- 1000 grams = 1 kilogram = 35.274 ounces = 2.205 pounds
- 1500 grams = 1.5 kilograms = 52.91 ounces = 3.307 pounds
- 2000 grams = 2 kilograms = 70.548 ounces = 4.409 pounds
- 3000 grams = 3 kilograms = 105.82 ounces = 6.614 pounds
- 4000 grams = 4 kilograms = 141.1 ounces = 8.818 pounds
- 5000 grams = 5 kilograms = 176.37 ounces = 11.023 pounds
Volume conversion charts
The metric system uses milliliters and liters to measure volume, while the imperial system has several units such as fluid ounces, cups, pints, quarts, and gallons.
As mentioned earlier, there are differences in the volume units of the British imperial system and the US customary system. Rest assured, the conversion charts below include conversions for both of these systems.
Imperial to Metric volume conversion
The chart below explains some of the common conversions such as the number of milliliters in a cup, liters in a gallon, liters in a quart, liters in a pint, and more.
US customary system
- 1 teaspoon = 4.93 milliliters = 0.0049 liters
- 1 tablespoon = 14.787 milliliters = 0.0148 liters
- ½ cup = 118.294 milliliters = 0.118 liters
- 1 cup = 236.588 milliliters = 0.237 liters
- 1 pint = 473.176 milliliters = 0.473 liters
- 1 quart = 946.353 milliliters = 0.946 liters
- ½ gallon = 1892.71 milliliters = 1.893 liters
- 1 gallon = 3785.41 milliliters = 3.785 liters
Metric to Imperial volume conversion
If you’re trying to convert metric volume to imperial, this chart will help you easily convert milliliters to ounces, milliliters to cups, liters to quarts, liters to pints, liters to ounces, and liters to gallons.
US customary system
- 50 milliliters = 1.691 fluid ounces = 0.2113 cups = 0.1056 pints = 0.0528 quarts = 0.0132 gallons
- 100 milliliters = 3.381 fluid ounces = 0.4227 cups = 0.211 pints = 0.1056 quarts = 0.0264 gallons
- 250 milliliters = 8.453 fluid ounces = 1.0567 cups = 0.528 pints = 0.264 quarts = 0.066 gallons
- 500 milliliters = 16.91 fluid ounces = 2.113 cups = 1.056 pints = 0.528 quarts = 0.132 gallons
- 1 liter = 33.814 fluid ounces = 4.227 cups = 2.113 pints = 1.0567 quarts = 0.264 gallons
- 2 liters = 67.63 fluid ounces = 8.455 cups = 4.227 pints = 2.113 quarts = 0.528 gallons
- 5 liters = 169.07 fluid ounces = 21.134 cups = 10.57 pints = 5.283 quarts = 1.321 gallons
The differences
The metric system and the imperial system are two different systems of measurement used worldwide for various purposes. While the metric system has been adopted by almost every country, the imperial system is used in only three countries – the United States, Liberia, and Myanmar.
The units of the metric system include the meter for length, the kilogram for mass, and the liter for volume, while the units of the imperial system include the pound for weight, the foot for length, and the gallon for volume.
The metric system is a decimal-based system where units are related by factors of ten. This makes it easy to convert between units by simply moving the decimal point.
On the other hand, the imperial system is an older system with units based on historical origins and practical considerations. The relationships between these units are often more complex, making conversions less straightforward than in the metric system.
Which is better?
The imperial system, with measurements like inches and feet, can sometimes be simpler to grasp in daily life. It can be easier to picture an inch or a foot than a centimeter or a meter. On the other hand, conversions in the metric system are much simpler.
Each system has its unique characteristics and aspects, and the preferred option can depend on factors such as geographic location, specific needs, and individual preference.