How Many Zeros in a Quadrillion?

Quadrillion's Position on the Short-Scale Ladder

The short answer: exactly 15 zeros. The prefix quadri- means four, referring to quadrillion's position as the fourth named step above a million on the short scale.

How Many Zeros Separate a Quadrillion from a Trillion?

A quadrillion is exactly 1,000 times larger than a trillion. A trillion has 12 zeros; a quadrillion has 15 — three additional zeros representing that factor of one thousand. To see short-scale versus long-scale usage and nine zeros after the leading 1, read how many zeros does a billion have.

If a trillion seconds is roughly 31,700 years, then a quadrillion seconds is closer to 31.7 million years.

• 1 quadrillion = 1,000 trillion
• 1 quadrillion = 1,000,000 billion
• 1 quadrillion = 1,000,000,000 million — a billion million

Quick Zero-Counting Trick

Count in groups of three after the leading 1: thousand, million, billion, trillion, quadrillion — each group adds three zeros to the last.

Trillion

12 zeros — 1,000,000,000,000

Quadrillion

15 zeros — 1,000,000,000,000,000

Quintillion

18 zeros — 1,000,000,000,000,000,000

How to Write a Quadrillion

A quadrillion follows the same set of accepted forms as the other short-scale giants. To see zero counts for 10 million and 100 million and short-scale naming, read how many zeros does a million have.

Standard, Scientific, and Shorthand Forms

• Standard form: 1,000,000,000,000,000
• Scientific notation: 1015
• Shorthand: 1 quadrillion is rarely abbreviated in finance, unlike million/billion/trillion, since figures rarely reach this scale outside of national and global accounting

Real-World References at the Quadrillion Scale

The total notional value of global derivatives markets has been estimated in the hundreds of trillions to low quadrillions of dollars. Cell counts across the human microbiome are also sometimes quoted near the quadrillion range.

Zeros Comparison Table

How Many Zeros Does a Long-Scale Quadrillion Have?

In the long-scale numbering system — historically used across continental Europe — a quadrillion means something very different: 1024, or 1 followed by 24 zeros. The long scale defines each new "-illion" as a million times the previous one, rather than a thousand times, so a long-scale quadrillion equals what the short scale calls a septillion.

For practical purposes, if you're reading an English-language source published in the US or UK after the 1970s, "quadrillion" almost certainly refers to 15 zeros. The long-scale meaning has largely faded from everyday English use.

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Zeros in a Quadrillion: FAQ

What comes before a quadrillion?

Quick answer

Hundred trillion (100,000,000,000,000) comes right before a quadrillion.

What comes after a quadrillion?

Quick answer

Ten quadrillion comes next, followed by hundred quadrillion and then quintillion.

How many digits does a quadrillion have?

A quadrillion has 16 digits in total — that's the digit 1 followed by 15 zeros.

How many zeros in 2 quadrillion? In 10 quadrillion?

Two quadrillion keeps the same 15 zeros — only the leading digit changes. Ten quadrillion adds one more, for 16 zeros total.

Is a 15-digit number always a quadrillion?

No. A 15-digit number ranges from 100,000,000,000,000 to 999,999,999,999,999 — that's hundreds of trillions, not a quadrillion. A quadrillion is the first 16-digit number.

How many zeros in a quadrillion in the British system?

Under the old British long-scale system, a quadrillion meant 10²⁴ — nine more zeros than today's short-scale quadrillion. Modern British English now follows the short scale, so a quadrillion in the UK matches US usage at 15 zeros.