How Many Zeros in an Undecillion?
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. Learn more about zeros in a trillion.
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. Learn more about how many zeros does a quindecillion have.
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.
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. Learn more about how many zeros in a centillion.
How Many Zeros in 10 Undecillion and 100 Undecillion?
- 1 undecillion =
1036— 36 zeros - 10 undecillion =
1037— 37 zeros - 100 undecillion =
1038— 38 zeros
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.