How many terabytes are in a petabyte?

Using the SI decimal standard: 1 PB = 1,000 TB. Using the IEC binary standard: 1 PiB (pebibyte) = 1,024 TiB (tebibytes). Storage manufacturers use PB; most operating systems report in PiB but often label them "PB."

Why does my OS show a different terabyte count than the vendor spec?

Operating systems display sizes in tebibytes (powers of 1,024), while vendors rate capacity in SI terabytes (powers of 1,000). Since 1 PiB = 1,024 TiB and 1 PB = 1,000 TB, the same byte count results in a different number depending on which standard is used.

What is the difference between PB and PiB?

PB (petabyte) follows the SI decimal system: 1 PB = 1,000 TB = 1,000,000,000,000,000 bytes. PiB (pebibyte) follows the IEC binary system: 1 PiB = 1,024 TiB = 1,125,899,906,842,624 bytes. 1 PiB is about 12.6% larger than 1 PB.

How do I convert petabytes to terabytes?

Multiply the petabyte value by 1,000 to get SI terabytes (TB). Multiply pebibytes by 1,024 to get binary tebibytes (TiB). For hardware and cloud storage, multiplying by 1,000 matches what vendors advertise.

How accurate is this converter for very large values?

The converter uses JavaScript 64-bit floating-point (IEEE 754 double precision), which handles integers exactly up to 2^53. For any practical storage size in petabytes, the result is accurate to the display precision shown.

Petabytes to Terabytes Converter

Enter a petabyte value and instantly get terabytes (TB, decimal SI) and tebibytes (TiB, binary IEC), plus a quick-reference table.

Input — Petabytes

Number of petabytes

SI vs. binary: 1 PB (petabyte, decimal) = 1,000 TB. The same 1 PB byte count is approximately 909.495 TiB. A PiB is a different input unit and equals exactly 1,024 TiB.

Results

Enter a petabyte value and click Convert.

Reference Table — Common Petabyte Counts

Quick lookup for typical data center and cloud storage sizes.

Petabytes (PB)	TB (SI, ×1,000)	TiB (same PB byte count)	Typical example

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Summary

Enter a petabyte value and instantly get terabytes (TB, decimal SI) and tebibytes (TiB, binary IEC), plus a quick-reference table.

How it works

Enter the number of petabytes in the input field.
The tool multiplies by 1,000 to get decimal terabytes (TB, SI).
It converts the same 10¹⁵-byte PB value to binary tebibytes by dividing by 2⁴⁰.
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 TB and TiB.

Use cases

Estimate how many terabytes of disk are needed to store a petabyte-scale dataset.
Translate cloud storage costs quoted per petabyte into a terabyte-level budget.
Convert data center capacity figures from petabytes to terabytes for procurement.
Understand backup job sizes when the scheduler reports in petabytes but drives are measured in terabytes.
Cross-reference OS-reported sizes (TiB) against hardware specs (TB) at scale.
Verify storage estimates when migrating large object stores or data lakes.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu