How Many Zeros in a Quintillion?

A quintillion is written as: 1,000,000,000,000,000,000
That's: A 1 followed by eighteen zeros or 19 digits total (including the 1)

So the answer is: There are 18 zeros in a quintillion.

What Is a Quintillion?

A quintillion is one of the largest named numbers we commonly use — usually in the context of astronomy, data science, and supercomputing.

A quintillion is:

1,000 quadrillions
1,000,000 trillions
1,000,000,000 billions
1,000,000,000,000,000,000 in numeric form
10¹⁸ in scientific notation

Every time you move up a level (thousand → million → billion → …), you add 3 more zeros. So quintillion is five jumps from thousand.

Zeros in Large Numbers — Comparison Table

Number Name	Numeric Form	Number of Zeros
Thousand	1,000	3
Million	1,000,000	6
Billion	1,000,000,000	9
Trillion	1,000,000,000,000	12
Quadrillion	1,000,000,000,000,000	15
Quintillion	1,000,000,000,000,000,000	18
Sextillion	1,000,000,000,000,000,000,000	21
Septillion	1,000,000,000,000,000,000,000,000	24

Real-World Examples of a Quintillion

While the word quintillion sounds sci-fi, it's used in real-world scientific and technological contexts:

Astronomy
The estimated number of atoms in a grain of sand is in the quintillions.
Light travels about 9.46 quintillion meters in a year (that's a light-year!).
Supercomputing & Data
Supercomputers are measured in exaflops (a quintillion operations per second).
→ 1 exaflop = 1 quintillion floating-point calculations per second.
Biology
The estimated number of bacteria on Earth is over 5 quintillion!

Quadrillion Comparison Table

Scale	Name	Zeros	Relative Size
10⁶	Million	6	Base level
10⁹	Billion	9	1,000 millions
10¹²	Trillion	12	1,000 billions
10¹⁵	Quadrillion	15	1,000 trillions
10¹⁸	Quintillion	18	1,000 quadrillions
10²¹	Sextillion	21	1,000 quintillions
10²⁴	Septillion	24	1,000 sextillions

Questions & Answers

How many zeros in 2 quintillion?

2 quintillion = 2,000,000,000,000,000,000
That’s a 2 followed by 18 zeros.

How many zeros in 10 quintillion?

10 quintillion = 10,000,000,000,000,000,000
That’s a 1 followed by 19 zeros.

How many zeros in 100 quintillion?

100 quintillion = 100,000,000,000,000,000,000
That’s a 1 followed by 20 zeros.

How many zeros in half a quintillion?

0.5 quintillion = 500,000,000,000,000,000
That’s a 5 followed by 17 zeros.

What Comes Before Quintillion?

The number that comes before a quintillion is a quadrillion.

Quadrillion = 1,000,000,000,000,000 (that’s 15 zeros)
It’s written as 10¹⁵ in scientific notation

A quintillion is a thousand quadrillions.

What Comes After Quintillion?

The next number after a quintillion is a sextillion.

Sextillion = 1,000,000,000,000,000,000,000 (that’s 21 zeros)
It’s written as 10²¹

A sextillion is a thousand quintillions.

Name	Number of Zeros	Scientific Notation
Quadrillion	15	10¹⁵
Quintillion	18	10¹⁸
Sextillion	21	10²¹

How many digits does a quintillion have?

A quintillion has 19 digits in total — that’s the digit 1 followed by 18 zeros.

Is an 18-digit number a quintillion?

Almost! An 18-digit number is very close to a quintillion, but a true quintillion is 1 followed by 18 zeros, which makes it a 19-digit number in total.

How many zeros in a quintillion in the British system?

Historically, British long scale defined quintillion as 10^30 (1 followed by 30 zeros). Today, both UK and US use the short scale: 1 followed by 18 zeros.

Visualizing a Quintillion

Need a mental image to grasp a number this enormous? Try this:

Pennies:
1 quintillion pennies would weigh over 2.8 billion tons — enough to sink entire continents.
Seconds:
1 quintillion seconds is over 31.7 billion years — more than twice the estimated age of the universe!
Digital Data:
If your hard drive held 1 quintillion bytes (a zettabyte), it could store over 250 billion HD movies.

Quintillion

A quintillion has 18 zeros
It equals 1,000,000,000,000,000,000
Scientific form: 10¹⁸
It's 1,000 times bigger than a quadrillion
Used in astronomy, data science, and biology

A quintillion isn't just a big number — it's a gateway to cosmic and computational thinking. From stars and atoms to supercomputers and bacteria, numbers this large are all around us — silently measuring the universe we live in.