Decillion — Definition, Formula & Examples

A decillion is the number 1 followed by 33 zeros. It equals one thousand nonillion, or

10^{33}

In the American naming system (short scale), a decillion is defined as $10^{33}$ , representing the eleventh power of one thousand beyond unity: $1{,}000^{11}$ . In the long scale used in some European countries, a decillion instead equals $10^{60}$ .

Key Formula

1 \text{ decillion} = 10^{33}

Where:

$10^{33}$ = A 1 followed by 33 zeros

Worked Example

Problem: Write out one decillion as a whole number.

Step 1: Start with 1 and write 33 zeros after it.

1\underbrace{000{,}000{,}000{,}000{,}000{,}000{,}000{,}000{,}000{,}000{,}000}_{33 \text{ zeros}}

Step 2: Count the groups of three zeros. There are 11 groups, matching the pattern: thousand, million, billion, trillion, quadrillion, quintillion, sextillion, septillion, octillion, nonillion, decillion.

Answer: One decillion = 1,000,000,000,000,000,000,000,000,000,000,000 (a 1 followed by 33 zeros).

Why It Matters

Large number names like decillion help you read and compare quantities in science, such as estimating the number of atoms or particles. Knowing the naming pattern also makes it easier to learn even bigger names like undecillion (

10^{36}

) and beyond.

Common Mistakes

Mistake: Confusing the American (short scale) and British/European (long scale) values. In the long scale, a decillion is

10^{60}

, not

10^{33}

Correction: In U.S. math classes, a decillion always means

10^{33}

. Be aware of which system a source uses.