BIG NUMBER GUIDE
What Is a Googol?
Quick answer: A googol is 10^100, or the digit 1 followed by exactly 100 zeros.
The number in one line
Exponential notation makes a googol easy to write: 10^100. Every time a power of ten rises by one, another zero is added. A million is 10^6, a billion is 10^9, and a googol is 10^100. It is a perfectly ordinary finite number, even though writing every digit is impractical in everyday work.
Where the word “googol” came from
The word was suggested in the late 1930s by Milton Sirotta, the young nephew of mathematician Edward Kasner. Kasner used it in his book Mathematics and the Imagination to give people a memorable name for an enormous quantity. The search company Google later chose a spelling inspired by “googol,” but a googol is a mathematical term, not a count of web pages.
How large is it?
A googol is vastly larger than a billion or a trillion. The jump is not small: a googol is 10^91 times larger than a billion. Physical comparisons eventually fail, but the number is useful because it shows what place value and exponents can do. It also helps separate “very large” from “beyond easy visualization.”
Googol and googolplex
A googolplex is 10 raised to a googol power: 10^(10^100). That means it is a 1 followed by a googol zeros. A googolplex is still finite, yet its decimal expansion could not fit in the observable universe. The contrast is a good reminder that exponents create scale much faster than ordinary counting.
Explore the scale yourself
Use the free Number Lab to move from one zero to one thousand and see the pattern in real time.
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