- Short history of units - from feet to meters
- Different systems of measurement
- Prefixes - metric conversion table
- How to use the measurement conversion calculator
- Temperature conversion calculator
- Length conversion calculator
- Area conversion calculator
- Volume conversion calculator
- Weight conversion calculator
Our measurement conversion calculator includes five unit converters: a temperature conversion calculator, a length conversion calculator, an area conversion calculator, a volume conversion calculator, and a weight conversion calculator. The unit conversion calculator includes numerous units, so you can easily switch between the metric conversion, the imperial system, and the United States customary units.
Go right ahead to convert Celsius to Fahrenheit, feet to meters, pounds to kilograms (lbs to kg), and even light years to Sun radii! This measurement converter is particularly useful if you need to convert units of various types, so you don't need to switch between different converters all the time.
The conversion calculator is divided into "metric," "imperial/US," and "other" sections, so you can learn which units belong to which system, and focus on just one type, if, for example, you need just a metric conversion calculator.
The text below includes a few examples of conversion, a metric conversion table, and more.
Short history of units - from feet to meters
A long time ago, before globalization began, but after humans had come down from the trees, measurement systems were needed for communication and trade. These early systems were, so to speak, "down-to-earth" - they were named after parts of the body, vessels, and other basic elements of everyday life. For instance, in Poland, people used: łokieć (ell), stopa (foot), dłoń (palm), palec (finger), and ziarno (grain).
Units were defined locally. Other than the Polish, many nations (including England, Greece, Rome, China, and France) used the foot as a part of their measurement system, but its size varied, even from city to city.
The Finns were inventive enough to come up with more extravagant units:
- peninkulma – the furthest distance from which a barking dog can be heard (c. 10 km)
- poronkusema – the distance a reindeer could travel without stopping to urinate (c. 7.5 km)
- tynnyrinala – the area (of field) that could be sown with one barrel of grain (4936.5 m2)
As the world became more and more interconnected, the need for one universal system grew. Imagine if scientists across the globe had to translate units into local ones, like French pied du roi (king's foot).
To cut a long story short, nations began to unify their units, as it made communication and trade simpler. The Enlightenment and the French Revolution gave rise to the metric system, which preceded to spread around the world.
Different systems of measurement
The metric system is now used in almost every countries. It is arranged around the decimal system, and in which the basic units are taken from the natural world (e.g., the meter is based on the dimensions of Earth). Its modern (i.e., far more developed than the version from the 18th century) form is The International System of Units (SI).
US customary units are still the primary system of measurement in the US and are used to some extent in Canada and Liberia.
In the UK the imperial units are still in use. Like US units, they derive from earlier English units. Although the two systems use the same names of units, they have different values. So be careful, UK gallon is not the same as US gallon.
Prefixes - metric conversion table
To understand metric conversion, it is useful to know what SI unit prefixes mean. Take a look at the metric conversion chart below:
How to interpret this metric conversion chart? For example, one megabyte is equal to million bytes:
1 MB = 1,000,000 B
Expressed in scientific notation:
1 MB = 10⁶ B
So, any time you see a unit in this form:
prefix + base unit
like "Megabyte," know that it's equal to the base unit multiplied the appropriate number of times.
A few more examples:
1 hectoliter = 100 liters
1 decagram = 10 grams
1 kilometer = 1,000 meters
1 nanosecond = 10⁻⁹ second
🙋 You can read more about working with bytes as units in our byte conversion tool.
How to use the measurement conversion calculator
Choose the type of conversion - select the temperature, length, area, volume, or weight converter.
If your desired unit is not displayed, choose it from the list of units (e.g., click °C and change it to °R) or switch to the advanced mode to show more variables.
Enter the value you'd like to calculate into the appropriate unit field.
Read the results of conversion.
Temperature conversion calculator
The temperature converter includes the following units:
🙋 If you want to know more about temperature and its conversion, or need to see a temperature conversion chart, check out our separate temperature conversion tool.
Length conversion calculator
The length converter includes following units:
- meters and centimeters
- thousandths of an inch
- feet and inches
- nautical miles
- Sun radii
- light years
- astronomical units
How to convert the metric length units?
Earlier, we discussed metric unit prefixes. So, if you want to know how many meters are in one kilometer, just remember "kilo" means "thousand". What if you wanted to answer the opposite question? - how many kilometers are in a meter? The answer is the multiplicative inverse: one-thousandth - 1/1000.
Finally, the third scenario - you want to switch between units where both of them are not the base units e.g., from decagrams to micrograms. To do that:
Convert the first unit (dag) to the basic unit (g):
1 dag = 10 g
Convert the basic unit (g) to the second unit (µg):
1 g = 10⁶ µg
Multiply two results:
1 dag = 10 * 10⁶ µg
1 dag = 10⁷ µg
💡 For a conversion table, and more information (how many feet in a meter, a definition of a meter, etc.) about length, see the length converter.
Area conversion calculator
The area conversion calculator includes the following units:
- square millimeters
- square centimeters
- square decimeters
- square meters
- square kilometers
- square inches
- square feet
- square yards
- square miles
Metric area unit conversion
Converting between metric area units is slightly more difficult than converting between length units. Let's answer the question - how many square meters are in one square kilometer? Remember prefixes? Kilo = thousand, but 1 km² is NOT equal to 1,000 m². Why?
First, what is a square meter? You can imagine it as a square with a side equal to 1 m:
m² = m * m
Let's see how many square meters would fit in one square kilometer:
1 km² = 1 km * 1 km
1 km² = 1,000 m * 1,000 m
1 km² = 1,000,000 m² = 10⁶ m²
One square kilometer equals one million square meters. To know it, you can simply square the "prefix value":
kilo = 1000
kilo² = 1000²
kilo² = 1,000,000
💡 To find out more, go to our area converter.
Volume conversion calculator
The volume conversion calculator includes following units:
- cubic nanometers
- cubic micrometers
- cubic millimeters
- cubic centimeters
- cubic decimeters
- cubic meters
- cubic kilometers
- cubic inches
- cubic feet
- cubic yards
- cubic miles
- US fluid ounces
- UK fluid ounces
- US pints
- UK pints
- US quarts
- UK quarts
- US gallons
- UK gallons
- US customary cups/glasses (236.59ml)
- tablespoons (15ml)
- teaspoons (5ml)
Metric volume unit conversion
Switching between cubic SI units is analogous to squared units, only the "prefix value" is cubed, not squared.
For example, how many cubic centimeters are in thirteen cubic meters?
m³ = m * m * m
1 m = 100 cm
13 m³ = 13 * 100 cm * 100 cm * 100 cm
13 m³ = 13,000,000 cm³
🔎 If you're interested in converting imperial or US units, see the volume conversion chart.
Weight conversion calculator
The weight conversion calculator includes following units:
- metric tons
- US tons (short tons)
- UK tons (long tons)
- weights of the Earth
- weights of the Sun
- electron rest mass
- proton rest mass
- neutron test mass
- atomic mass units
- Troy ounces
Metric weight unit conversion
Converting weight units is analogous to length conversion - a microgram is 0.000001 of a gram because "micro" means "0.000001" and gram is the base unit.
🔎 If you'd like to read the explanation of switching between measurement systems (convert lbs to kg, m to in, etc.), check out the separate weight converter.