Long and short scales facts for kids

The long and short scales are two different ways to name very large numbers, like a billion or a trillion. They use the same words but give them different meanings! This can sometimes cause confusion.

The main difference is how they count up. The long scale is based on powers of one million (1,000,000). The short scale is based on powers of one thousand (1,000).

For numbers smaller than a thousand million (which is 1,000,000,000), both scales use the same names. But once you get to a thousand million or more, the names start to mean different things.

Understanding the Short Scale

In the short scale, each new "-illion" word after "million" is one thousand times bigger than the one before it.

• A billion (10⁹) means a thousand million.
• A trillion (10¹²) means a thousand billion.
• A quadrillion (10¹⁵) means a thousand trillion, and so on.

Understanding the Long Scale

In the long scale, each new "-illion" word after "million" is one million times bigger than the one before it.

• A billion (10¹²) means a million million.
• A trillion (10¹⁸) means a million billion.
• A quadrillion (10²⁴) means a million trillion, and so on.

Notice how a "billion" is 10⁹ in the short scale but 10¹² in the long scale! This is why it's important to know which scale is being used.

Where Are These Scales Used?

The way large numbers are named can vary from country to country.

The long scale is mostly used in:

• Most countries in continental Europe.
• Many French-speaking, Spanish-speaking, and Portuguese-speaking countries.
• An exception is Brazil, which uses the short scale.

The short scale is now used in:

• Most English-speaking countries.
• Most Arabic-speaking countries.
• Brazil.
• Countries that were part of the former Soviet Union.

Even though the names are similar in many languages because they come from the same origins, some parts of East Asia and South Asia have completely different ways of naming large numbers, like the Indian numbering system.

For a long time, the United Kingdom used the long scale, while the United States used the short scale. Because of this, people often called them the "British" and "American" systems. However, after 1974, the UK government officially adopted the short scale. So, today, the way numbers are named in the UK and the US is almost always the same.

The terms "short scale" (French: échelle courte) and "long scale" (French: échelle longue) were first used by a French mathematician named Geneviève Guitel in 1975.

To avoid confusion, especially in science, the SI (which is a global system of measurement) suggests using metric prefixes. These prefixes, like "kilo-" or "mega-", always mean the same amount, no matter the country or language. However, for counting money, both the long and short scales are still commonly used.

See also

A friendly robot to guide you.

In Spanish: Escalas numéricas larga y corta para niños