A zettabyte (ZB) is a unit of digital data equal to 1,000 exabytes (EB), or 10^21 bytes, as defined by the international system of units (SI). Its binary counterpart, the zebibyte (ZiB), is 2^70 bytes, about 18.1% more. The zettabyte sits below the yottabyte (YB). It is far beyond anything a business buys; it is used mainly to describe data volumes across the whole world.
At a glance
- Decimal: 1 ZB = 10^21 bytes = 1,000 EB = one billion TB. Binary counterpart: 1 zebibyte (ZiB) = 2^70 bytes.
- The gap between the unit and its binary counterpart is about 18.1%.
- As a rough illustration, zettabytes describe estimates of all data created worldwide in a year, or total internet traffic over a year, not any single organization’s holdings.
- For buyers, zettabytes appear mainly in analyst reports and vendor marketing about data growth.
What problem it solves
The zettabyte gives researchers, analysts and industry bodies a unit for global totals: how much data the world creates, copies, stores or sends across networks each year. Expressing those totals in exabytes or petabytes would produce unwieldy numbers. The unit is therefore common in market forecasts, policy discussions about data center energy use and network capacity planning at national or global scale.
How it works
Decimal and binary values. 1 ZB = 1,000 EB = 10^21 bytes; 1 ZiB = 1,024 EiB = 2^70 bytes. Global estimates are almost always stated in decimal units.
What the figures count. Published zettabyte figures measure different things: data created, data captured, data copied or replicated, data stored at a point in time, or data transmitted over networks. A figure for data created in a year can be much larger than the amount actually stored, because much data is temporary, overwritten or never kept. When reading such statistics, check which of these the source is measuring and whether it is an estimate, a forecast or a measurement.
Putting it in familiar units. One zettabyte is one billion terabytes, or one million petabytes. A large enterprise with several petabytes of data holds a tiny fraction of one zettabyte, which is why the unit does not appear in storage quotes.
Why the numbers grow. Video, sensors, backups and replicated copies all add to global totals. The same growth drivers often apply inside organizations, but at the scale of terabytes and petabytes (PB).
When it matters for buyers
- Reading vendor marketing. Statements that the world will create a certain number of zettabytes are often used to justify a storage, backup or analytics purchase. They describe the market, not your requirements.
- Building a business case. Replace global figures with your own measured growth: data under management today, annual growth, change rates and retention periods.
- Understanding provider economics. Global growth helps explain why storage and network providers keep investing in capacity, and why pricing per GB changes over time.
For sizing your own storage, our file and object storage page explains how we help buyers compare options on the volumes they actually hold.
Questions to ask vendors
- What is the source and date of any global data statistic in your proposal, and is it a forecast or a measurement?
- Does the figure count data created, stored or transmitted?
- How does your sizing for our environment use our own data, rather than market-wide growth figures?
- What growth rate have you assumed for our data, and what does the price look like if it is wrong?
- If our data grows faster than planned, how are additional terabytes priced?
How it differs from a zebibyte (ZiB)
A zebibyte is 2^70 bytes, about 18.1% more than a decimal zettabyte. The binary unit is seldom used at this scale, since global estimates are rounded far more coarsely than the gap between the two. The glossary term Binary Prefixes covers the binary units in more detail.