In the internationally accepted SI system of measurement units, length is measured in terms of meters (or metres). Units derived from the meter such as centimeter, kilometer, millimeter are also used. In the United States, length is measured in Miles, Inches, foot, yard, etc.

Just a fun fact, in astronomy, large distances are measured in terms of light years (which is a unit of length and not time). Parsec is another unit used for measuring large distances.

The SI unit for mass is the kilogram (kg). Other units derived from the kilogram such as gram, milligram and tonne are also used. In the United States, mass is measured in pounds (lbs).

Some other units of length include atomic mass unit, solar mass (mass of our sun) and slug.

If the measurements are being taken in metrics the various units of lengths are millimeter (mm), centimeters (cm), meters (M), and kilometers (km); for mass it is grams(g) and kilograms (kg). Science measurements are always done in metrics because it is an international language among scientists that all scientists worldwide understand

There are several systems of measurement.

In the **English (Imperial) system**, Length is measured in inch (in), foot (ft), yard(yd) and mile.

There are 12 inches in a foot.

An inch is roughly equal to 2.5 centimetres.

A foot is roughly equal to 30 centimetres.

A mile is roughly equal to 1.5 kilometres.

Mass is measured in ounce(oz), pound (lb) and ton.

There are 16 ounces in a pound.

An ounce is roughly equal to 25 grams.

A pound (454g) is equal to just under half a kilogram (500 g).

The **Metric system** is based on the fundamental units of measure for length meter (m) and mass gram(g).

In the **International system of units (SI)** the base unit for the measurement of length is meter (m) and for mass is Kilogram (kg).

Base units in the Metric system can be converted into units that are more appropriate for the quantity being measured by adding a prefix to the name of the base unit.

For example , 1 kilometre = 1000 m , 1 decimetre = 1/10 m

1 centimetre = 1/100 m

1 millimetre = 1/1000 m