1billion

1 billion is the number 1,000,000,000. In decimal notation it equals one thousand million and is a commonly used large quantity in everyday and technical contexts, such as population counts, national debt figures, and products or events measured on a large scale.

Naming conventions vary by historical system. In the short scale used today in most English-speaking countries, a billion equals 10^9. In the long-scale system once common in parts of Europe, a billion was defined as 10^12, with 10^9 referred to as a milliard, and 10^6 as a million. Some languages still use "milliard" to avoid confusion with "billion".

In science and computing, 1 billion is frequently written as 1 × 10^9. The SI prefix giga- denotes this quantity (as in gigabyte, gigahertz). In computing, there is a persistent distinction between decimal gigabytes (10^9 bytes) and binary gibibytes (2^30 bytes, 1 GiB), which can affect storage specifications and marketing.

Related topics include the short and long scales, the terms milliard and billion in different languages, and the distinction between decimal prefixes and binary data units.