How Many Zeros in a Decillion?
A decillion has 33 zeros: 1,000,000,000,000,000,000,000,000,000,000,000. In scientific notation, the zeros in a decillion are represented as 1033. The number contains 11 groups of three zeros beyond the leading 1 — a helpful way to verify the count without losing track. One decillion follows nonillion (1030) and precedes undecillion (1036) in the short-scale sequence used in the United States and modern scientific contexts. In the long-scale system used in parts of Europe, the same word means something entirely different: 1060, or 1 followed by 60 zeros. Learn more about how many zeros does a centillion have.
A decillion has
33
zeros
- Written Form
- 1 followed by 33 zeros
- Scientific
- 10³³
What Number Is 1,000,000,000,000,000,000,000,000,000,000,000?
The number 1,000,000,000,000,000,000,000,000,000,000,000 is called a decillion. It is the digit 1 followed by exactly 33 zeros, equal to 1033 in scientific notation. To confirm the zero count, divide the written number into comma-separated groups: there are eleven groups of three digits after the leading 1, giving 3 × 11 = 33 zeros. See also: Quadrillion zeros.
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.
Quantities in the decillion range appear mainly in theoretical physics and cosmology. The number of possible quantum states in certain physical systems can reach this order of magnitude, and some estimates of the total number of chemical reactions possible in the universe involve numbers at or beyond 1033.
How Many Zeros Does a Decillion Have in the Long Scale?
In the long-scale system, a decillion has 60 zeros (1060), compared to 33 in the short scale. The gap between the two conventions grows with every step up the naming ladder — by the time you reach decillion, the long-scale value is 1027 times larger than the short-scale one, a difference equal to one octillion. See also: How many zeros does a vigintillion have.
Short scale vs long scale at a glance for decillion:
| System | Zeros | Scientific Notation |
|---|---|---|
| Short scale (US / modern UK) | 33 | 1033 |
| Long scale (continental Europe) | 60 | 1060 |
In practice, any English-language source from the past 50 years — whether American or British — uses the short-scale definition. So how many zeros are in a decillion? Always 33 in modern English usage, and 1033 in scientific notation.