How Many Zeros in an Undecillion?
By Vinitha Published Updated
How many zeros in an undecillion? An undecillion has 36 zeros: 1,000,000,000,000,000,000,000,000,000,000,000,000, or 1036 in scientific notation. It is the 12th named power of one thousand in the short-scale system used in the United States and United Kingdom. For more on short-scale versus long-scale usage, see how many zeros does a trillion have.
An undecillion has
36
zeros
- Written Form
- 1 followed by 36 zeros
- Scientific
- 10³⁶
The Undec- Prefix Explained
The direct answer: exactly 36 zeros. The prefix undec- combines un- (one) and dec- (ten), indicating the eleventh group of three zeros beyond the ones place.
Short Scale vs Long Scale
- Short scale (US / modern UK)
- 36 zeros —
1036 - Long scale (continental Europe)
- 66 zeros —
1066
The 30-zero gap between the two systems means the long-scale undecillion is a nonillion times larger than the short-scale one. For all modern English-language purposes — science, finance, education — undecillion means 36 zeros. More on how centillion compares with other named numbers: how many zeros in a centillion.
Undecillion vs Its Neighbors
| Name | Zeros | Scientific notation |
|---|---|---|
| Decillion | 33 | 1033 |
| Undecillion | 36 | 1036 |
| Duodecillion | 39 | 1039 |
Real-World Scale
The observable universe contains roughly 1080 atoms, so an undecillion (1036) still falls about 44 orders of magnitude short of that count. How many zeros does an unvigintillion have covers Latin prefixes in -illion names alongside the digit 1 followed by 66 zeros.
How Many Zeros in 10 Undecillion and 100 Undecillion?
- 1 undecillion =
1036— 36 zeros - 10 undecillion =
1037— 37 zeros - 100 undecillion =
1038— 38 zeros
Watch: How Many Zeros in an Undecillion?
How many zeros in an undecillion? An undecillion has 36 zeros — 1 followed by 36 zeros. Watch this short video for the zero count, the written form and the notation at a glance.
Zeros in an Undecillion: FAQ
What comes before an undecillion?
Quick answer
Hundred decillion comes right before an undecillion.
What comes after an undecillion?
Quick answer
Ten undecillion comes next, followed by hundred undecillion and then duodecillion.
How many digits does an undecillion have?
An undecillion has 37 digits in total — that's the digit 1 followed by 36 zeros.
How many zeros in 2 undecillion? In half an undecillion?
Two undecillion keeps the same 36 zeros. Half an undecillion has 35 trailing zeros after the 5.
Is a 36-digit number always an undecillion?
No. A 36-digit number tops out at hundreds of decillions — an undecillion is the first 37-digit number.
How many zeros in an undecillion in the British system?
Under the old long-scale system, an undecillion meant 1066 — 30 more zeros than today's short-scale undecillion.
About the Author
Designer and Developer · Palakkad, Kerala, India
Vinitha holds a bachelor's degree in Textile and Apparel Design from Avinashilingam University, plus a C-Tech certificate in Graphic Design from Image Creative Education. She builds free, no-clutter reference tools like How Many Zeros. Read her full bio.