How Many Zeros in a Zettabyte?
By Vinitha Published Updated
How many zeros in a zettabyte? A zettabyte (ZB) has 21 zeros in the decimal system: 1,000,000,000,000,000,000,000 bytes, or 1021 bytes. One zettabyte equals 1,000 exabytes or one sextillion bytes. Questions about why drives show about 931 MB per advertised GB are answered in zeros in a gigabyte.
A zettabyte has
21
zeros
- Written Form
- 1 followed by 21 zeros bytes
- Scientific
- 10²¹ bytes
- Binary (IEC)
- 2⁷⁰ bytes (ZiB)
Verifying the Zero Count in a Zettabyte
The direct answer: exactly 21 zeros, equal to one sextillion. The binary zebibyte (ZiB = 270) is not a round decimal number and carries no clean trailing-zero count — about 18.1% larger than the decimal zettabyte. For more on app and photo file sizes, see zeros in a megabyte.
Is a Zettabyte Bigger Than a Terabyte?
Yes — by an enormous margin. A zettabyte is one billion times larger than a terabyte, a gap spanning nine orders of magnitude: 1 ZB = 1,000,000,000 TB.
A 1 TB hard drive — which holds roughly 500 hours of HD video — would need to be duplicated one billion times to reach a single zettabyte.
Zettabyte's Place in the Storage Scale
| Unit | Zeros | Bytes |
|---|---|---|
| Terabyte (TB) | 12 | 1012 |
| Petabyte (PB) | 15 | 1015 |
| Exabyte (EB) | 18 | 1018 |
| Zettabyte (ZB) | 21 | 1021 |
Is a Zettabyte or Yottabyte Bigger?
A yottabyte is bigger — exactly 1,000 times larger. A zettabyte has 21 zeros, while a yottabyte has 24. The zettabyte has become the practical unit for describing global data volumes; industry research firms project total worldwide data creation in the tens of zettabytes per year.
Zettabyte-Scale Data Sources
- Total worldwide annual data creation and replication
- Cumulative global internet traffic over several years
- Combined storage capacity across all cloud data centers
Watch: How Many Zeros in a Zettabyte?
How many zeros in a zettabyte? A zettabyte has 21 zeros — 1 followed by 21 zeros bytes. Watch this short video for the zero count, the written form and the notation at a glance.
Zeros in a Zettabyte: FAQ
What comes before a zettabyte?
Quick answer
Exabyte comes right before zettabyte — a zettabyte is exactly 1,000 exabytes.
What comes after a zettabyte?
Quick answer
Yottabyte comes next, followed by ronnabyte.
How many digits does a zettabyte have?
A zettabyte has 22 digits in total — that's the digit 1 followed by 21 zeros.
Is a zettabyte the same as a sextillion bytes?
Yes — a decimal zettabyte (1021 bytes) is exactly one sextillion bytes.
Why is "zettabyte" used to describe global data volume?
Because worldwide annual data creation has grown into the tens of zettabytes, making it the most natural scale for "big data" discussions at a planetary level.
How many zettabytes are in a yottabyte?
Exactly 1,000 zettabytes make one yottabyte.
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.