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How Many Zeros in a Decillion?

How many zeros in a decillion? A decillion has 33 zeros: 1,000,000,000,000,000,000,000,000,000,000,000, or 1033 in scientific notation. It follows nonillion (1030) and precedes undecillion (1036) in the short-scale sequence used in the United States and modern scientific contexts. Learn more about unvigintillion zeros.

A decillion has

33

zeros

Written Form
1 followed by 33 zeros
Scientific
10³³

Verifying the Zero Count in a Decillion

The direct answer: exactly 33 zeros. The number contains 11 groups of three zeros beyond the leading 1 — divide the written form into comma-separated groups and you'll count eleven of them. Learn more about how many zeros in a quattuordecillion.

How many zeros in a Decillion? 33 zeros, written as 1 followed by 33 zeros (10³³).
How many zeros in a Decillion? — howmanyzeros.org

What Number Is 1,000,000,000,000,000,000,000,000,000,000,000?

That number is a decillion. The deci- prefix means ten, referring to the tenth power of one thousand beyond the starting point: 1,00011 = 1033. This naming logic applies consistently across the short-scale sequence — each new "-illion" adds three zeros and increments the Latin prefix by one.

Some estimates of the total number of possible chemical reactions in the universe reach the decillion range — one of the few contexts where a number this large connects to physical science.

Decillion vs Its Neighbors

Decillion's position in the short-scale sequence.
NameZerosScientific notation
Nonillion301030
Decillion331033
Undecillion361036

Quick Zero-Counting Trick

  • 1,000,000,000,000,000,000,000,000,000,000,000 (one decillion) — 33 zeros
  • 10,000,000,000,000,000,000,000,000,000,000,000 (ten decillion) — 34 zeros
  • 100,000,000,000,000,000,000,000,000,000,000,000 (hundred decillion) — 35 zeros

How Many Zeros Does a Decillion Have in the Long Scale?

In the long-scale system used in parts of Europe, a decillion means something entirely different: 1060, or 60 zeros. The gap between the two conventions grows with every step up the naming ladder — by decillion, the long-scale value is 1027 times larger, a difference equal to one octillion. See also: Zeros in a quadrillion.


Zeros in a Decillion: FAQ

What comes before a decillion?
Quick answer

Hundred nonillion comes right before a decillion.

What comes after a decillion?
Quick answer

Ten decillion comes next, followed by hundred decillion and then undecillion.

How many digits does a decillion have?

A decillion has 34 digits in total — that's the digit 1 followed by 33 zeros.

How many zeros in 2 decillion? In half a decillion?

Two decillion keeps the same 33 zeros. Half a decillion has 32 trailing zeros after the 5.

Is a 33-digit number always a decillion?

No. A 33-digit number tops out at hundreds of nonillions before reaching a decillion — a decillion is the first 34-digit number.

How many zeros in a decillion in the British system?

Under the old long-scale system, a decillion meant 1060. In practice, any English-language source from the past 50 years — American or British — uses the short-scale definition: 33 zeros.