How many gigabytes are in a petabyte?

Using the SI decimal standard: 1 PB = 1,000,000 GB (10^15 bytes ÷ 10^9 bytes/GB). Using the IEC binary standard: 1 PiB (pebibyte) = 1,125,899.9 GiB (2^50 bytes ÷ 2^30 bytes/GiB). Storage manufacturers and cloud providers use the SI definition.

What is the difference between PB and PiB?

PB (petabyte) follows the SI decimal system: 1 PB = 1,000 TB = 10^15 bytes. PiB (pebibyte) follows the IEC binary system: 1 PiB = 1,024 TiB = 2^50 bytes. 1 PiB is about 12.6% larger than 1 PB.

How do I convert terabytes to gigabytes first?

To go from terabytes to gigabytes: 1 TB = 1,000 GB (SI). So 1 PB = 1,000 TB = 1,000,000 GB. Multiply your petabyte value by 1,000,000 for the GB result.

Why does my storage system show fewer GB than expected for a given PB value?

Storage hardware is rated in SI petabytes (powers of 1,000). Operating systems report capacity in binary gibibytes (powers of 1,024) but often label them "GB." Since 1 GiB > 1 GB, the same byte count produces a smaller number in GiB, making the drive appear smaller.

How accurate is this converter for very large petabyte values?

The converter uses JavaScript 64-bit floating-point (IEEE 754 double precision), which handles integers exactly up to 2^53. For petabyte-scale inputs under ~9,000 PB, the result is accurate to at least 15 significant digits — more than enough for practical storage calculations.

Petabytes to Gigabytes Converter

Name: Petabytes to Gigabytes Converter
Availability: InStock
Author: Nham Vu

Enter a petabyte value and instantly get gigabytes (GB, decimal SI) and gibibytes (GiB, binary IEC), plus a reference table.

Input — Petabytes

Number of petabytes

SI vs. binary: 1 PB (petabyte, decimal) = 1,000,000 GB. 1 PiB (pebibyte, binary) = 1,125,899.9 GiB. Cloud and storage vendors use SI; OS tools often report binary values labeled "GB."

Results

Enter a petabyte value and click Convert.

Reference Table — Common Petabyte Values

Quick lookup for typical large-scale storage sizes.

Petabytes (PB)	GB (SI, ×10⁶)	GiB (binary, ×1,048,576)	Typical example

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Summary

Enter a petabyte value and instantly get gigabytes (GB, decimal SI) and gibibytes (GiB, binary IEC), plus a reference table.

How it works

Enter the number of petabytes in the input field.
The tool multiplies by 1,000,000 to get decimal gigabytes (GB, SI).
It also multiplies by 1,048,576 to convert pebibytes (PiB) to gibibytes (GiB, binary IEC).
Results appear instantly with up to 10 significant digits.
Use the copy buttons to grab any result value.
Scroll down for a reference table of common petabyte counts in GB and GiB.

Use cases

Estimate how many gigabytes a data-lake or backup archive of several petabytes will use.
Compare cloud storage pricing quoted per GB against a petabyte-scale dataset.
Convert data-transfer figures reported in petabytes into gigabytes for capacity planning.
Cross-check SI-based petabyte specs against OS-reported gibibyte values.
Translate large-scale analytics pipeline storage requirements from PB to GB.
Verify data-center rack storage totals when mixing petabyte and gigabyte specs.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu