PB to GB converter

What is a petabyte?

A petabyte (PB) is a unit of digital information storage in the International System of Units (SI). It represents 1,000,000,000,000,000 bytes (or $10^{15}$ bytes). Petabytes are commonly used to quantify large-scale data storage, such as in cloud infrastructure, scientific research datasets, or enterprise-level databases. For perspective, streaming 4K video for one hour consumes roughly 7–10 GB; a single PB could store over 100,000 hours of such video.

What is a gigabyte?

A gigabyte (GB) is another SI unit of digital information, equal to 1,000,000,000 bytes (or $10^{9}$ bytes). It is widely used to describe everyday storage capacities, such as smartphone memory (e.g., 128 GB) or file sizes (e.g., a 2-hour HD movie may occupy 4–8 GB).

SI system vs. binary system (IEC standard)

Digital storage units follow two distinct measurement systems:

1. SI (base-10): Uses powers of 10. Units include PB, TB, GB, MB, and kB.
2. Binary (base-2, IEC standard): Uses powers of 2. Units include pebibyte (PiB), tebibyte (TiB), gibibyte (GiB), and mebibyte (MiB).

The confusion arises because manufacturers and operating systems historically used “GB” to represent $2^{30}$ bytes (≈1.074 billion bytes) instead of the SI definition. To resolve this, the International Electrotechnical Commission (IEC) introduced binary prefixes in 1998. For example:

• $1\ \text{PiB} = 1,125,899,906,842,624\ \text{bytes} = 2^{50}\ \text{bytes}$
• $1\ \text{GiB} = 1,073,741,824\ \text{bytes} = 2^{30}\ \text{bytes}$

Conversion formulas

SI system (PB to GB)

$1\ \text{PB} = 10^{15}\ \text{bytes} = 10^{6}\ \text{GB} = 1,000,000\ \text{GB}$
To convert PB to GB:
$\text{GB} = \text{PB} \times 1,000,000$

Binary system (PiB to GiB)

$1\ \text{PiB} = 2^{50}\ \text{bytes} = 2^{20}\ \text{GiB} = 1,048,576\ \text{GiB}$
To convert PiB to GiB:
$\text{GiB} = \text{PiB} \times 1,048,576$

Step-by-step conversion examples

Example 1: Converting 2.5 PB to GB (SI system)

Using the SI formula:
$2.5\ \text{PB} \times 1,000,000 = 2,500,000\ \text{GB}$
This means 2.5 petabytes equal 2.5 million gigabytes.

Example 2: Converting 3 PiB to GiB (binary system)

Using the binary formula:
$3\ \text{PiB} \times 1,048,576 = 3,145,728\ \text{GiB}$
Thus, 3 pebibytes equal 3,145,728 gibibytes.

Historical context of data measurement

The ambiguity between base-10 and base-2 units dates back to the 1960s, when early computer systems adopted binary prefixes for memory addressing. However, storage manufacturers later used decimal units for marketing (e.g., labeling a 1 TB drive as 1,000 GB instead of 931 GiB). This discrepancy led to consumer complaints and the IEC’s formalization of binary prefixes (e.g., KiB, MiB, GiB) in 1998. Despite this, many operating systems still report storage in SI units, causing confusion.

Practical applications and examples

• Cloud storage: A data center with 50 PB of capacity can store $50 \times 1,000,000 = 50,000,000\ \text{GB}$.
• Video platforms: If YouTube processes 500 hours of video per minute (~3 PB daily), this equals 3,000,000 GB/day.
• Gaming: A modern video game averaging 80 GB would occupy $1\ \text{PB} \div 80\ \text{GB} = 12,500$ games.

Notes on correct unit usage

1. Check the context: Operating systems like Windows often report storage in GiB but label it as “GB.”
2. Precision in contracts: Cloud providers may specify PB or PiB; a 1 PiB plan offers ~12.6% more storage than 1 PB.
3. Scientific research: Adhere to SI units for consistency in publications.

Frequently asked questions

How many GB in a PB?

In the SI system:
$1\ \text{PB} = 1,000,000\ \text{GB}$
For example, 0.75 PB equals:
$0.75 \times 1,000,000 = 750,000\ \text{GB}$

Why is there a difference between PB and PiB?

PB uses base-10 $(10^{15})$, while PiB uses base-2 $(2^{50})$. Since $2^{50} ≈ 1.1259 \times 10^{15}$, 1 PiB is approximately 12.6% larger than 1 PB.

How do I convert 5 PiB to GiB?

Using the binary formula:
$5\ \text{PiB} \times 1,048,576\ \text{GiB/PiB} = 5,242,880\ \text{GiB}$

Are GB and GiB interchangeable?

No. For instance, 1 GB = 1,000,000,000 bytes, whereas 1 GiB = 1,073,741,824 bytes. A 256 GB SSD is approximately 238.4 GiB.

How much data does a 1 PB drive hold in GiB?

First, convert PB to bytes:
$1\ \text{PB} = 10^{15}\ \text{bytes}$
Then convert bytes to GiB:
$\frac{10^{15}}{2^{30}} ≈ 931,322.5746\ \text{GiB}$
Thus, 1 PB ≈ 931,322.57 GiB.