quadrillion

American  

[kwo-dril-yuhn] / kwɒˈdrɪl yən /

noun

plural

quadrillions,

plural

quadrillion

1. a cardinal number represented in the U.S. by 1 followed by 15 zeros, and in Great Britain by 1 followed by 24 zeros.

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adjective

1. amounting to one quadrillion in number.

quadrillion British  

/ kwɒˈdrɪljən /

noun

1. US and Canadian word: septillion.  (in Britain) the number represented as one followed by 24 zeros (10 ²⁴ )

2. (in the US and Canada) the number represented as one followed by 15 zeros (10 ¹⁵ )

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determiner

1. 1. amounting to this number

      a quadrillion atoms

   2. ( as pronoun )

      a quadrillion

Other Word Forms

• quadrillionth noun

Etymology

Origin of quadrillion

1665–75; quadr- + -illion (as in million )

Explanation

It's a little time consuming to write out the number one quadrillion, since it's a one and fifteen zeros. It's probably a good time to brush up on big numbers, now that billions and even trillions are bandied about as if they were mere dozens. A quadrillion is one followed by fifteen zeroes. If you're looking for a mnemonic, the root word, quad, "four" from the Latin quadri, refers to the number of groups of three zeroes that follow one thousand.

Example Sentences

Google said in October that it handles more than 1.3 quadrillion tokens monthly, which is roughly 43 trillion daily.

From Barron's • Feb. 14, 2026

He noted Google’s announcement that it had processed 1.3 quadrillion monthly tokens in October, up from 480 trillion in April.

From MarketWatch • Nov. 4, 2025

This month, Google said the figure had reached 1.3 quadrillion.

From The Wall Street Journal • Oct. 14, 2025

The quadrillion boomer men and four Buddhist monks in performance-fabric bucket hats—what on earth were they hiding under there, besides their sun-sensitive scalps?

From Slate • Aug. 13, 2025

So we skip the pancakes with all the cooking and measuring, and jump to the eating—by the way, sausage sandwiches are always a quadrillion times better than TV dinners, that's for sure.

From "Sunny" by Jason Reynolds