Length Unit

The area designates the surface layer of an object.
The term area is used in mathematics whereas the term area is used mainly for the measurement of the surface of land.

Base unit: the square meter

The square meter (m2 symbol) is the basic unit for measuring an area. 1 square meter corresponds to the surface of a square of one meter of side.

Main multiple and submultiple of the square meter:
Unit Symbol Area in square meters
The kilometer square km² 1 000 000
The square hectometre hm² 10 000
The square decameter dam² 100
The square decimeter dm² 0,01
The square centimeter cm² 0.000 1
The square millimeter mm² 0.000 001

you can use our area converter to convert area measures between different units.

Other surface units

    As with length units, there is a set of Anglo-American units for measuring an area: the square inch is 6.4516 cm², the square feet (square feet in English) Is worth about 929 cm ², the square yard is worth about 8 361 cm ², the square mile is about 2.59 km ².
    For the measurement of the surface area of ​​a site, use is made of the acres and the hectare.
    The acre and acre are ancient units of measure of the area of ​​land whose values ​​have changed considerably over time and by region.

The volume of an object measures its extension in space in all three directions at the same time.
Base unit: the cubic meter

The volume is measured in cubic meter (symbol m³) in the international system.

Multiple principal and submultiple of cubic meter:
Unit Symbol Volume in cubic meters
The cubic kilometer km³ 1,000,000,000
The cubic hectometer hm³ 1 000 000
The cube damascus decameter 1,000
The cubic decimeter dm³ 0.001
The cubic centimeter cm³ 0.000 001
The cubic millimeter mm³ 0, 000 000 001
Base unit: liter

The liter (symbol L or l) is used to measure the volumes of liquids and solids.

One liter corresponds to the volume of a cube of one decimeter of side or a cubic decimeter.

The main multiples and submultiples of the liter are:
Unit Symbol Volume in liters
The hectolitre hl 100
The decaliter dal 10
The deciliter dl 0.1
The centiliter cl 0.01
The milliliter ml 0.001

Conversion table cubic meter / liter
m³ dm³ l dl
1 cubic meter (m³) = 1 1,000 1,000 10,000
1 cubic decimeter (dm³) = 0.001 1 1 10
1 liter (a) = 0.001
1 deciliter (dl) = 0.000 1 0.1 0.1

you can use our volume converter to convert your volume measures.

Other volume units

    As for length units and area units, there is a set of Anglo-American units for measuring a volume: cubic inch (cubic inch in English, cu in symbol) is 16,387 cm³, Cubic foot (cubic foot in English, symbol cu ​​ft) is 28 317 cm³, the cubic yard (cub yard) is worth about 0,764 m³.
    The US gallon (US gal symbol) is a US unit used to measure the volume of liquids and is defined as 231 cubic inches, or 3,785,411,784 liters. The US gallon is divided into 128 ounces.
    The barrel (symbol bbl or bbl) is a unit of measurement used for crude oil and its derivatives. One barrel of oil corresponds to 158.9873 liters.
    The stere is an illegal unit in France since December 31, 1977, but is still commonly used for measuring the volume of firewood. A stem of wood is equivalent to a volume of one cubic meter, ie a stack of logs 1 meter long over a height of 1 meter and a width of 1 meter. The stere expresses the outside volume of the wood pile, without taking into account the existing spaces between the logs.
    The spoon is used as a volume unit in the dosage of different ingredients or intake of medication. The teaspoon represents a volume of 5 ml. One tablespoon contains three teaspoons.

The mass of an object measures the quantity of matter contained in that object. The official unit of measure of mass is the kilogram (kg), but there are several systems and units of measurement of the mass.

Note :

The mass is often mistakenly confused with weight, whose official unit is the Newton (N), and which measures the force of attraction of a star on a body (gravity). So the mass of a man will be found to be on Earth or on the Moon, while his weight will be considerably reduced on the Moon (about 6 times lighter).

Base unit: kilogram (kg)

In the international system, the official unit of mass measurement is the kilogram (kg symbol).

The table below lists the main multiples and sub-multiples of the kilogram:
Unit Symbol Weight in kilograms
The tonne t 1 000
The kilogram kg 1
The Hg hg 0.1
 The decagram dag 0,01
 The gram g 0.001

you can convert weight measures with our weight converter

For measurement of masses less than gramme there are also submultiples of the gram:
Unit Symbol Weight in grams
 The decigram dg 0,1
 The centigram cg 0.01
 The milligram mg 0.001

The kilogram was originally defined in 1795 as being equal to the mass of one liter of pure water at 4 ° C. The reference prototype of the kilogram was manufactured in France in 1799 and serves as a reference for the current kilogram. There are several copies kept in different countries. The photograph below, dated 1915, represents one of the two national prototypes of the United States. Made of an alloy of platinum and iridium it is protected by two glass bells.

Other mass units

    -The quintal (symbol q): one hundredweight is 100 kg. This unit is still used today, in particular for the measurement of agricultural yield expressed in quintals per hectare.
    -The pound is an old unit of mass divided into ounces and whose definition has varied according to time and place. Two mass units called “books” still exist today:
    -In France, the pound was worth between 380 g and 552 g in the Middle Ages. In 1812, the metric pound was defined as 500 grams. The pound and half pound (250g) are still used today in food and cooking (one pound of butter = 500 g butter for example).
    -The English pound, symbol lb, which is equal to 453,59237 g.
    -The ounce is a unit of mass whose value is between 24 and 33 grams depending on the place and the time.
    -The ounce avoirdupois (oz symbol) is still used today in the United States and the Commonwealth.
 It is 28.349 g.
    -The Troy ounce is equivalent to 1/3 Troy (after the city of Troyes). It is used in particular for the quotation of precious metals such as gold or platinum, and is 31.1034768 g.
    -The Dutch ounce (ons) is not an official unit, but is still sometimes used: 1 ons = 100 g.
    -The grain, for which there are several definitions:
        Former unit of measure of mass worth about 53,114 mg in France, about the mass of a good grain of wheat or barley.
        Unit of mass always used in jewelery to express the weight of beads or diamonds (1 grain = 0,049 g).
        Mass unit used in the armory to indicate the weight of bales and powder loads used by firearms (1 grain = 64.8 mg).
    -Talent is an ancient unit used in the days of Great Greece and the Roman Empire. Its value has varied according to time and place. In Athens, a talent equaled 25.86 kg of silver and represented the volume of water needed to fill an amphora.

Temperature is a physical magnitude that expresses the degree or level of cold or warmth of bodies or environment. In the international system of units, the unit of temperature is the Kelvin. Below and in general, we will discuss other units of measurement of the temperature.
We can differentiate, so to speak, two categories of units of measure of temperature: absolute and relative.

– Absolute are those which start from the absolute zero, which is the lowest possible theoretical temperature and which corresponds to the point at which the molecules and atoms of a system have the smallest possible thermal energy.
– Kelvin (international system): represented by the letter K and without symbol “º” of degree. It was created by William Thomson, based on degrees Celsius, thus establishing zero point in absolute zero (-273.15 ºC) and retaining the same dimension for degrees. This unit was established in the international system of units in 1954.

– Relative because they are compared with an established physicochemical process which always occurs at the same temperature.
– Degrees Celsius (international system): also called centigrade degree, represented by the symbol ºC. This unit of measurement is defined by selecting the freezing point of water at 0º and the boiling point of water at 100º, both measurements in a pressure atmosphere and dividing the scale into 100 equal parts in Each of which corresponds to 1 degree. This scale was proposed by Anders Celsius in 1742, a Swedish physicist and astronomer.
– Degrees Fahrenheit (international system): this divide between the freezing and evaporation points of ammonium chloride dissolutions. Thus the proposition of Gabriel Fahrenheit in 1724, establishes the zero and the cent for the temperatures of freezing and evaporation of the ammonium chloride in the water. He used a portable mercury thermometer in which he introduced a mixture of crushed ice and ammonium chloride in equal parts. This concentrated salt solution gave the lowest possible temperature in the laboratory at that time. Then he made another mixture of crushed ice and pure water, which determined the 30 ºF point, which was then set at 32 ºF (melting point of ice) and then exposed the portable thermometer to steam, Boiling water to obtain point 212 ºF (boiling point of water). The difference between the two points is 180 ºF, which divided into 180 equal parts determines the degree Fahrenheit.

you can use our Temperature converter to convert your temperature measures.

For a moment (one moment: For example, the plane takes off precisely at 9h 43mn) or a duration (The journey will last 2h 45mn), we use the measures of time.

To measure time or duration over the years, calibrated instruments (sundials, hourglasses, clepsydres, watches, clocks, chronometers, etc.)

    Depending on the situation, the durations are indicated in years, months, days, hours, minutes, or seconds:

        1 year = 12 months = 365 or 366 days

        1 day = 24 hours (h)

        1 hour = 60 minutes = 3600 seconds

For longer, older periods, the millennium and the century will be used.

        Thus if we realized a chronological frieze from antiquity to our days, we should calibrate it in millennia and centuries.

        Today we are in the 3rd millennium (from J.C.) and the 21st century (= 21st century.) The centuries are often expressed in Roman numerals)

        A millennium = 10 centuries = 1,000 years

        1 century = 100 years

        Christopher Columbus discovered America in 1492 (15th century).

        The nineteenth century begins on January 1, 1801 and ends on December 31, 1900.

To convert hours into minutes or minutes to seconds or vice versa, it is useful to familiarize yourself with multiples of 60

For example :

120 min = 60 x 2 = 2 h
385 s = 360 + 25 = (60 x 6) + 25 = 6 min 25 s

To convert your time measures you can use our Time Conversion Tool.