An exabyte (EB) is a unit of digital data equal to 1,000 petabytes (PB), or 10^18 bytes, as defined by the international system of units (SI). Its binary counterpart, the exbibyte (EiB), is 2^60 bytes, about 15.3% more. The exabyte sits below the zettabyte (ZB). It is rarely a unit businesses buy in, but it appears often in how large cloud and storage providers describe their platforms.
At a glance
- Decimal: 1 EB = 10^18 bytes = 1,000 PB = 1,000,000 TB. Binary counterpart: 1 exbibyte (EiB) = 2^60 bytes.
- The gap between the unit and its binary counterpart is about 15.3%.
- As a rough illustration, exabytes describe the total data held by a large cloud platform, a major internet service or a large scientific programme, not by a typical business.
- For buyers, exabytes mainly show up in provider scale claims and in the size limits of storage platforms.
What problem it solves
The exabyte gives a unit for data held across entire platforms and industries. Large cloud providers, content platforms and research facilities collect data at a rate where petabytes become awkward to count. It also appears in technical limits: some file systems and object storage platforms state their maximum supported capacity in exabytes, signalling that a single customer is unlikely to reach the ceiling.
How it works
Decimal and binary values. 1 EB = 1,000 PB = 10^18 bytes; 1 EiB = 1,024 PiB = 2^60 bytes. At this scale the binary and decimal values differ by more than 150 PB per exabyte, so it matters whether a limit labelled EB really means EiB.
Where exabytes are stored. Exabyte-scale systems are almost always distributed: data is spread across many servers, drives and often several data centers, using object storage or scale-out file systems. See file systems and object storage for how these models work. Organizations that pool logs, files and events into a shared data lake on such platforms benefit from that scale without operating it themselves.
Putting it in familiar units. One exabyte is one million terabytes. An organization holding a few petabytes, which is already a large estate, holds well under one percent of an exabyte.
Platform claims. Providers sometimes cite the total exabytes they store, or the durability their systems are designed for, as evidence of maturity. Those claims describe the platform as a whole. What a customer can rely on is set by the service terms for its own account, region and storage tier.
When it matters for buyers
- Evaluating provider claims. Treat “we store exabytes” as context, not as a commitment. Ask instead about the tier, redundancy and service level that apply to your data.
- Checking platform limits. If a file system or object store supports exabytes, capacity limits are unlikely to constrain you; per-bucket, per-object or per-account limits are more likely to matter.
- Long-term planning. Few mid-market organizations will reach exabytes, but fast-growing data sets in video, imaging or sensor data can make petabyte planning urgent sooner than expected.
See our file and object storage page for how we help buyers compare storage providers on the commitments that apply to them.
Questions to ask vendors
- Which of your scale or durability figures are contractual for our account, and which describe the platform as a whole?
- What are the practical limits per volume, file system, bucket or object that would affect us?
- Are your published maximum capacities stated in decimal or binary units?
- How is our data placed across facilities, and what does the service level commit to?
How it differs from an exbibyte (EiB)
An exbibyte is 2^60 bytes, about 15.3% more than a decimal exabyte. Technical documentation for file systems and operating systems often states limits in binary units, sometimes labelled EB, while industry and marketing figures usually use decimal units. The glossary term Binary Prefixes covers the binary units in more detail.