How Many Zeros in a Billion? US vs UK Billion Explained

Q: How many zeros are in a septillion?

In the short scale, a septillion has 24 zeros (10^24). In the long scale, it would have 42 zeros (10^42).

Q: What is a googol?

A googol is the number 1 followed by 100 zeros, written as 10^100. It was coined by a child in the 1930s and later named Google's search engine.

Q: How many zeros are in a billion in French?

In French, 'billion' means 1,000,000,000,000 — 12 zeros (long scale). The term 'milliard' (9 zeros) is used for the short-scale billion.

Q: How many zeros in a quindecillion?

In the short scale, a quindecillion has 48 zeros (10^48). In the long scale, it would have 90 zeros.

Q: How many zeros are in a million million?

'Million million' = 1,000,000 × 1,000,000 = 1,000,000,000,000, which has 12 zeros. In the long scale, this is called a billion. In the short scale, it's called a trillion.

Q: What is the largest named number with zeros?

Acceptable named large numbers include 'centillion' (303 zeros in short scale, 600 zeros in long scale). 'Zillion' and 'gazillion' are not real numerical terms — they're informal words meaning an indefinitely large number.

It sounds like a simple question, but the answer changes depending on where you grew up and what you learned in school. A billion in the United States has nine zeros, but in the United Kingdom it used to be a very different number — twelve zeros.

Zeros in a US billion: 9 ·
Zeros in a UK billion (historical): 12 ·
Zeros in a US trillion: 12 ·
Zeros in a US quadrillion: 15 ·
Zeros in a million: 6

Quick snapshot

1Confirmed facts

US billion has 9 zeros (UK Parliament House of Commons Library (official guidance))
UK now officially uses short scale (9 zeros) (Wikipedia (encyclopedia reference))
Trillion in US has 12 zeros (Wikipedia (encyclopedia reference))

2What’s unclear

Some older British sources still use long scale in informal contexts (Oxford Learner’s Dictionaries (authoritative dictionary))
“Zillion” and “gazillion” are not real numerical terms (Wikipedia (encyclopedia reference))
The 1974 switch was a policy change, not a legal mandate, leading to occasional informal use of long scale (Numbers are confusing (educational reference))
The long scale is still used in many European languages for the word “billion” (Online Conversion (reference tool))

3Timeline signal

UK officially adopted short scale in 1974 (Numbers are confusing (educational reference))
US has used short scale since its founding (UK Parliament House of Commons Library (official guidance))

4What’s next

Global finance and science increasingly enforce short scale for clarity (UK Parliament House of Commons Library (official guidance))
Readers should verify which scale is used in older or non-English sources (Online Conversion (reference tool))

The paradox

The word “billion” means 1,000,000,000 in the US and modern UK — but in many European languages like French and German, “billion” still means 1,000,000,000,000. This false friend causes real confusion in international finance and education.

The difference between the two scales becomes clear in this comparison.

Zero counts for major number scales
Number	Short scale (US, modern UK)	Long scale (historical UK, many EU countries)
Million	6 zeros	6 zeros
Billion	9 zeros	12 zeros
Trillion	12 zeros	18 zeros
Quadrillion	15 zeros	24 zeros
Quintillion	18 zeros	30 zeros
Sextillion	21 zeros	36 zeros

Six rows, one pattern: every step in the short scale adds 3 zeros (×1,000), while every step in the long scale adds 6 zeros (×1,000,000). The difference grows exponentially as numbers get larger.

How many zeros are in $1 billion?

Zeros in a US billion

A US billion has 9 zeros: 1,000,000,000.
This is known as the short scale, where each step above a million is 1,000 times larger (UK Parliament House of Commons Library (official guidance)).
Amounts like $1 billion also have 9 zeros: $1,000,000,000.

Zeros in a British billion (historical)

Historically, a British billion had 12 zeros: 1,000,000,000,000.
This was the long scale, also called “one million million” (Oxford Learner’s Dictionaries (authoritative dictionary)).
Oxford Learner’s Dictionaries still labels the 12-zero sense as “British English, old-fashioned” — a warning to readers of older texts.

The implication: if you’re reading a British financial report from 1970, a billion meant one million million. Today it means one thousand million, just like the US.

What to watch

A 1970s UK government budget mentioning “one billion pounds” actually referred to 1,000,000,000,000 — twelve zeros. Today that same statement would mean just 1,000,000,000. Investors reading historical documents need to know which scale was used.

Is an American billion different to a UK billion?

Short scale vs long scale

Short scale: each step above a million is 1,000 times larger (×10³). Billion = 1,000,000,000 (9 zeros).
Long scale: each step above a million is 1,000,000 times larger (×10⁶). Billion = 1,000,000,000,000 (12 zeros).
The US uses short scale exclusively (Wikipedia (encyclopedia reference)).
Many European countries (France, Germany, Spain, Italy, Poland, Sweden) use long scale for their native translations of “billion” (Online Conversion (reference tool)).

When did the UK switch to short scale?

The UK officially adopted the short scale in 1974, following a government decision to align with US usage (Numbers are confusing (educational reference)).
Since then, official UK statistics use billion to mean 1,000,000,000 (UK Parliament House of Commons Library (official guidance)).

The catch: the 1974 switch wasn’t a legal mandate — it was a policy change. Some older British publications and older generations still occasionally use the long scale informally.

How many zeros are in a trillion?

Here is a comparison of trillion zero counts across the two scales.

Trillion zero counts by scale
Scale	Zeros	Written form
Short scale (US, modern UK)	12 zeros	1,000,000,000,000
Long scale (historical UK)	18 zeros	1,000,000,000,000,000,000

Two rows, one contrast: a short-scale trillion is 1,000 billion; a long-scale trillion is 1,000 billion in long-scale terms, which is actually 1,000,000 times larger.

Trillion zeros (US)

A US trillion has 12 zeros: 1,000,000,000,000.
In the short scale, trillion equals 10¹², or 1,000 billion (UK Parliament House of Commons Library (official guidance)).

Trillion zeros (UK historical)

A UK trillion historically had 18 zeros: 1,000,000,000,000,000,000.
In the long scale, trillion equals 10¹⁸ (UK Parliament House of Commons Library (official guidance)).

Why this matters: when the US federal budget exceeds $6 trillion, that’s 6,000,000,000,000 — but in France, “6 billions” would mean 6,000,000,000, just 6. Media translations of international budgets are a common source of numeric errors.

What is a quadrillion?

Quadrillion zeros

A quadrillion (short scale) has 15 zeros: 1,000,000,000,000,000.
This is 10¹⁵, which is 1,000 trillion.

Beyond quadrillion: quintillion, sextillion

Each step in the short scale adds 3 zeros: quintillion (18 zeros), sextillion (21 zeros), septillion (24 zeros).
This pattern continues: name + “illion” = (prefix + 1) × 3 zeros, roughly (Arithmetic – Names of large numbers (academic reference)).

The trade-off: the short scale is simpler for everyday use (×1,000 each step), but when scientists talk about the number of stars in the universe (a sextillion) or grains of sand on Earth (around 7.5 quintillion), the long scale would double those numbers in ways most people don’t expect.

“The short scale proceeds by powers of one thousand, whereas the long scale proceeds by powers of one million.”

— Arithmetic – Names of large numbers (academic reference)

Are you a billionaire if you have 1 billion?

Definition of a billionaire

Yes, having $1 billion in net worth makes you a billionaire.
Billionaire status is based on net worth in US dollars, using the short scale (Forbes (business publication)).
That means at least $1,000,000,000 — nine zeros — in assets minus liabilities.

Net worth thresholds

Millionaire: $1,000,000 (6 zeros).
Billionaire: $1,000,000,000 (9 zeros).
Trillionaire: $1,000,000,000,000 (12 zeros) — no individual has reached this yet as of 2025 (Wikipedia (encyclopedia reference)).

What this means: a billionaire has exactly 1,000 times more zeros than a millionaire. A trillionaire would have 1,000 times more than a billionaire. The gap between millionaire and billionaire is the same as the gap between billionaire and trillionaire — and no one has crossed the second gap yet.

“In the short scale, one billion equals 10⁹, which is 1,000,000,000 and has 9 zeros.”

— UK Parliament House of Commons Library (official research briefing)

Additional sources

simple.wikipedia.org, medium.com, reddit.com, youtube.com, en.wikipedia.org

Frequently asked questions

How many zeros are in a septillion?

In the short scale, a septillion has 24 zeros (10²⁴). In the long scale, it would have 42 zeros (10⁴²).

What is a googol?

A googol is the number 1 followed by 100 zeros, written as 10¹⁰⁰. It was coined by a child in the 1930s and later named Google’s search engine.

How many zeros are in a billion in French?

In French, “billion” means 1,000,000,000,000 — 12 zeros (long scale). The term “milliard” (9 zeros) is used for the short-scale billion.

Is a billion the same in all countries?

No. English-speaking countries (US, UK, Canada, Australia) now use short scale (9 zeros). Many European, African, and South American countries use long scale (12 zeros) for their native word for “billion.”

How many zeros in a quindecillion?

In the short scale, a quindecillion has 48 zeros (10⁴⁸). In the long scale, it would have 90 zeros.

How many zeros are in a million million?

“Million million” = 1,000,000 × 1,000,000 = 1,000,000,000,000, which has 12 zeros. In the long scale, this is called a billion. In the short scale, it’s called a trillion.

What is the largest named number with zeros?

Acceptable named large numbers include “centillion” (303 zeros in short scale, 600 zeros in long scale). “Zillion” and “gazillion” are not real numerical terms — they’re informal words meaning an indefinitely large number.

These FAQs cover the most common confusions about large number scales.