How Many Zeros in a Centillion?
A centillion has 303 zeros: 10303. It is the digit 1 followed by 303 zeros, spanning 304 digits in total. The short-scale formula confirms the count: the 100th "-illion" after a million gives 3 × 100 + 3 = 303 zeros. Centillion is the largest formally named "-illion" number in standard English dictionaries, and in the short-scale US system it represents the endpoint of the systematic Latin-prefix naming chain. In the long-scale system used in parts of continental Europe, a centillion means 10600 — 600 zeros, exactly double the exponent. Despite its size, a centillion is astronomically smaller than a googolplex (1010100). Related: How many zeros does an undecillion have.
A centillion has
303
zeros
- Written Form
- 1 followed by 303 zeros
- Scientific
- 10³⁰³
What Does 1 Centillion Look Like?
Writing out one centillion in full requires placing the digit 1 and then writing 303 zeros — a task that, printed at normal font size, would span several pages. The number contains 101 groups of three digits: 1 followed by 101 comma-separated three-zero groups.
A centillion dollars, for perspective, is a number so large it has no connection to any real-world quantity. The total wealth of every person on Earth is measured in the low tens of trillions of dollars — roughly 1013. A centillion dollars exceeds that by 290 orders of magnitude, making it an entirely abstract concept rather than a financial quantity. Learn more about trillion zeros.
One hundred centillion (10305) has 305 zeros — two more than one centillion, following the standard rule that each factor of 100 adds two zeros to the exponent.
Is Centillion the Biggest Named Number?
Centillion is the largest number with a standard "-illion" name in most English dictionaries, but it is far from the largest number with any name at all. Numbers explicitly larger than a centillion include:
- Googol — 10100 (100 zeros) — actually smaller than a centillion
- Googolplex — 1010100 — incomprehensibly larger than a centillion
- Googolplexian — 10googolplex — larger still
Wait — a googol (10100) has only 100 zeros and is therefore smaller than a centillion (303 zeros). But a googolplex (1010100) has a googol of zeros, which is 10100 zeros — vastly more than 303. So the ordering is: googol < centillion < googolplex < googolplexian. Learn more about zeros in a decillion.
The naming sequence beyond centillion can in principle continue (uncentillion, duocentillion, etc.), but these names are not in standard dictionaries and are rarely encountered outside formal mathematical writing. For most practical purposes, centillion is treated as the practical upper bound of the "-illion" naming chain.