1,000,000,000 (one billion, short scale; one thousand million or one milliard, one yard, long scale) is the  natural number following 999,999,999 and preceding 1,000,000,001. With a number, "billion" can be abbreviated as b, bil or bn. 
In standard form, it is written as
1 × 10. The 9 metric prefix giga indicates 1,000,000,000 times the base unit. Its symbol is .
One billion years may be called an
in astronomy or geology.
British English (but not in American English), the word "billion" referred exclusively to a million millions (1,000,000,000,000). However, this is no longer common, and the word has been used to mean one thousand million (1,000,000,000) for several decades.
can also be used to refer to 1,000,000,000; whereas "milliard" is rarely used in English, milliard variations on this name often appear in  other languages.
South Asian numbering system, it is known as 100 crore or 1 arab.
1,000,000,000 is also the
cube of 1000.
Visualization of powers of ten from one to 1 billion
Sense of scale
The facts below give a sense of how large 1,000,000,000 (10
9) is in the context of time according to current scientific evidence:
9 seconds (1 gigasecond) equal 11,574 days, 1 hour, 46 minutes and 40 seconds (approximately 31.7 years, or 31 years, 8 months, 8 days). About 10
9 minutes ago, the Roman Empire was flourishing and Christianity was emerging. (10 9 minutes is roughly 1,901 years.) About 10
9 hours ago, modern human beings and their ancestors were living in the Stone Age (more precisely, the Middle Paleolithic). (10 9 hours is roughly 114,080 years.) About 10
9 days ago, , an ape-like creature related to an ancestor of modern humans, roamed the African Australopithecus savannas. (10 9 days is roughly 2.738 million years.) About 10
9 months ago, dinosaurs walked the Earth during the late Cretaceous. (10 9 months is roughly 83.3 million years.) About 10
9 years—a gigaannus—ago, the first multicellular eukaryotes appeared on Earth. About 10
9 decades ago, galaxies began to appear in the early Universe which was then 3.772 billion years old. (10 9 decades is exactly 10 billion years.) The universe is thought to be about 13.77 × 10 9 years old. 
9 inches is 15,783 miles (25,400 km), more than halfway around the world and thus sufficient to reach any point on the globe from any other point. 10
9 metres (called a gigametre) is almost three times the distance from the Earth to the Moon. 10 9 kilometres (called a terametre) is over six times the distance from the Earth to the Sun.
A billion square inches could make a square about one half mile on a side.
A bolt of finely woven 1000-TC bed sheet linen with a billion thread crossings would have an area of 40 square metres (48 sq yd), comparable to the floor area of a motel unit.
There are one billion cubic
millimetres in a cubic metre, and a billion cubic metres in a cubic kilometre. A billion grains of table salt or granulated sugar would occupy a volume of about 2.5 cubic feet (0.071 m
3). A billion cubic inches would be a volume comparable to a large commercial building slightly larger than a typical supermarket.
Any object that weighs one billion kilograms (2.2
×10 9 lb) would weigh about as much as 5,525 empty Boeing 747-400s. A cube of iron that weighs one billion pounds (450,000,000 kg) would be 38.62 metres (126.7 ft) on each side.
Any object that weighs 1 billion scruples would weigh as much as 9 Blue whales
A small mountain, slightly larger than
Stone Mountain in Georgia, United States, would weigh (have a mass of) a billion tons. There are billions of worker ants in the largest ant colony in the world,
which covers almost 4,000 miles (6,400 km) of the Mediterranean coast.  In 1804, the world population was one billion.
A is a cube; B consists of 1000 cubes the size of cube A, C consists of 1000 cubes the size of cube B; and D consists of 1000 cubes the size of cube C. Thus there are 1 million A-sized cubes in C; and 1,000,000,000 A-sized cubes in D.