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
  adjective
• 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

Every operation -- such as applying a quantum gate -- influences more than 2 quadrillion complex numerical values, a "2" with 15 zeros.

From Science Daily • May 11, 2026

She added she would have preferred to have a £63 quadrillion gift card to spend at the supermarket.

From BBC • Feb. 21, 2026

The effort relies on a supercomputer in Wyoming that can do nearly 20 quadrillion calculations a second using 328 Nvidia chips.

From The Wall Street Journal • Feb. 19, 2026

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

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