Convert petabytes to terabytes

Content last reviewed:2026-09-30

Type 1 PB and the converter shows 1,024 TB in the binary standard, the one Windows uses, or 1,000 TB in the decimal standard, the one drive makers use for capacity. You pick the standard with the toggle under the fields.

Petabytes

Terabytes

Unit standard

Binary (1024): what Windows and RAM use. Decimal (1000): what drive makers, macOS and search engines use.

What are a petabyte and a terabyte?

A petabyte (PB) is a unit of data equal to a quadrillion bytes, or 10¹⁵ B. A terabyte (TB) holds a trillion bytes, or 10¹² B, so a thousand terabytes fit in one petabyte. Each unit also has a twin counted in powers of two, with its own name: the pebibyte (PiB) of 2⁵⁰ bytes and the tebibyte (TiB) of 2⁴⁰ bytes[1].

Windows counts capacity in powers of two but labels the result with decimal symbols such as MB and GB[2]. That is why the converter lets you choose which of the two definitions you are converting.

How many terabytes are in a petabyte?

A petabyte has 1,024 terabytes in the binary standard and 1,000 terabytes in the decimal one. The conversion is a single multiplication: you multiply the number of petabytes by 1,024 or by 1,000. The number 1,024 is 2 to the power of 10, the power of two closest to a thousand, which is why computing uses it in place of a thousand.

Both results are in use because different people count differently. Storage makers give capacity in decimal, so 1 TB on a box means a trillion bytes, and newer versions of macOS and iOS count the same way[3]. Windows counts in binary, so it describes the same number of bytes with fewer terabytes.

Take 2.5 PB. In binary it comes to 2,560 TB, in decimal to 2,500 TB. The 60 TB gap is as much as three 20 TB drives hold, so check where a figure comes from before you convert it and set the converter to the same standard.

Rows of black server racks in a bright server room, with cable trays running under the ceiling — Rows of server racks stand in a server room, and cable trays run under the ceiling. Racks like these hold the storage arrays whose capacity is quoted in petabytes. Photo: imgix, Unsplash.

How do you convert PB to TB? Formula and Excel

The formula comes in two versions, one for each standard:

binary: TB = PB × 1,024,
decimal: TB = PB × 1,000.

Take a storage array sold as 1.2 PB. In the binary standard that is 1,228.8 TB, and in the decimal one 1,200 TB.

In Excel the CONVERT function handles bytes with prefixes. The formula =CONVERT(A2,"Pbyte","Tbyte") counts in decimal, and =CONVERT(A2,"Pibyte","Tibyte") in binary[4].

To go the other way, use the TB to PB converter, which also shows how many drives and tapes make up a petabyte. The data size converter gives a result in gigabytes and covers any other pair of units, from bytes to petabytes.

How many terabytes is a given number of petabytes?

The result in both standards side by side. The binary column matches the way Windows counts, and the decimal one the way drive and array makers state capacity.

Petabytes	Binary (1024)	Decimal (1000)
0.001 PB	1.024 TB	1 TB
0.01 PB	10.24 TB	10 TB
0.1 PB	102.4 TB	100 TB
0.25 PB	256 TB	250 TB
0.5 PB	512 TB	500 TB
1 PB	1,024 TB	1,000 TB
1.1 PB	1,126.4 TB	1,100 TB
1.2 PB	1,228.8 TB	1,200 TB
1.5 PB	1,536 TB	1,500 TB
1.6 PB	1,638.4 TB	1,600 TB
2 PB	2,048 TB	2,000 TB
2.5 PB	2,560 TB	2,500 TB
3 PB	3,072 TB	3,000 TB
4 PB	4,096 TB	4,000 TB
5 PB	5,120 TB	5,000 TB
10 PB	10,240 TB	10,000 TB
20 PB	20,480 TB	20,000 TB
50 PB	51,200 TB	50,000 TB
100 PB	102,400 TB	100,000 TB
1,000 PB	1,024,000 TB	1,000,000 TB

The 2.5 PB row matches an estimate of the human brain's memory capacity that psychologist Paul Reber of Northwestern University gave in Scientific American in 2010. He added that the exact capacity of memory is hard to calculate[5].

How many tebibytes is a capacity the maker gives in petabytes?

Makers give capacity in decimal, in terabytes and petabytes. The table shows how many tebibytes and pebibytes sit behind their number, which is the figure you will see in Windows.

Capacity from the maker	Terabytes (TB)	Tebibytes (TiB)	Pebibytes (PiB)
0.5 PB	500 TB	454.747 TiB	0.4441 PiB
1 PB	1,000 TB	909.495 TiB	0.8882 PiB
2 PB	2,000 TB	1,818.989 TiB	1.7764 PiB
5 PB	5,000 TB	4,547.474 TiB	4.4409 PiB
10 PB	10,000 TB	9,094.947 TiB	8.8818 PiB

The gap between the two standards grows with every step. At the kilobyte it is 2.4%. At the terabyte it reaches 10.0%, and at the petabyte 12.6%[2].

What comes after a petabyte?

Each step is a thousand times bigger than the one before. To turn petabytes into exabytes, use the data unit converter, and for exabytes into zettabytes, the EB to ZB converter. The last column gives the year the prefix became part of the SI[6].

Unit	In bytes	In terabytes	SI prefix since
petabyte (PB)	10¹⁵ B	10³ TB	1975
exabyte (EB)	10¹⁸ B	10⁶ TB	1975
zettabyte (ZB)	10²¹ B	10⁹ TB	1991
yottabyte (YB)	10²⁴ B	10¹² TB	1991
ronnabyte (RB)	10²⁷ B	10¹⁵ TB	2022
quettabyte (QB)	10³⁰ B	10¹⁸ TB	2022

The 27th General Conference on Weights and Measures adopted the ronna and quetta prefixes in November 2022. The resolution points to the needs of data science, which will describe amounts of information above 10²⁴, and to the need to stop unofficial names from taking hold in practice[7].

Which ways of writing petabytes does this converter accept?

Paste the capacity the way you have it: with a decimal point, with commas between thousands, with the unit attached or straight from an array's data sheet. The field reads each of these and converts it on its own, and the table shows exactly what it does with each one. The converter worked out the results itself in the Binary (1024) standard.

What you type	What the converter shows	How we read it
1.5	1536 TB	The point marks the decimal part, so the field holds one and a half petabytes
1,500	1536000 TB	A comma before three digits groups thousands, so we count fifteen hundred petabytes. A note under the field says how we read it, and if you meant one and a half, type 1.5
1,5	1536 TB	A comma before a single digit can only be a decimal comma, the way European spreadsheets write it, so we count one and a half petabytes
12,500	12800000 TB	The comma separates thousands, so the field holds twelve thousand five hundred. A note under the field shows the other possible reading, 12.5.
2½	2560 TB	We add the ½ character copied from a document to the number in front of it
2.5e-3	2.56 TB	We read spreadsheet scientific notation as it is: 2.5e-3 means 0.0025 petabytes
Raw capacity: 1.2 PB	1228.8 TB	A whole line copied from an array's data sheet works too, because we take the number right before the unit symbol
2 TB	2 TB	Terabytes pasted into the petabytes field are written in as 0.00195313 PB, with a note under the field, so the result is the same 2 TB
1,000,204,886,016 bytes	0.9097 TB	A byte count from the disk Properties window is first converted to petabytes (0.00088836 PB) and then to terabytes
LTO-9 18 TB	18 TB	The digit in the tape name does not join the number: we take the 18 TB right before the unit and write it into the field as 0.0175781 PB

Which standard should you pick in the converter?

You set the standard with the Unit standard toggle under the fields. Pick it based on where the number comes from.

Capacity from a quote or a data sheet
Choose Decimal (1000). Drive, array and tape makers state capacity in decimal, so 1 PB in their documents means 1,000 TB.
A figure from File Explorer in Windows
Choose Binary (1024). That is how File Explorer counts, so the result will match what you see on screen.
A figure from Finder on a Mac
Choose Decimal (1000). Newer versions of macOS show capacity in decimal, the same way drive makers do.

Convert other units to Terabytes

GB to TB TiB to TB

Convert Petabytes to other units

PB to PiB PB to EB

Sources

Byte — Wikipedia
Binary prefix — Wikipedia
How storage capacity is measured on Apple devices — Apple
CONVERT function — Microsoft
What Is the Memory Capacity of the Human Brain? — Scientific American
SI prefixes — Bureau International des Poids et Mesures
Resolution 3 of the 27th CGPM (2022): On the extension of the range of SI prefixes — Bureau International des Poids et Mesures
Orion — Oak Ridge Leadership Computing Facility

Every figure in the tables was computed from the unit definitions and checked arithmetically before publication. Historical values and the names of local units come from the sources listed above.

Content last reviewed: September 30, 2026 · written and checked by the Arteon team

Frequently asked questions about petabytes and terabytes

What is a brontobyte?

Brontobyte is a name that circulates online for the step after the yottabyte. It is not a unit of the SI or of any IEC standard. Since 2022 the official steps after the yottabyte have been the units with the prefixes ronna (RB) and quetta (QB)[7]. The data unit converter converts both.

Does 1 PB of storage actually exist?

Yes, in disk arrays and tape libraries that join many drives into one pool. The Orion file system at Oak Ridge National Laboratory, which serves the Frontier supercomputer, has room for up to 700 PB of data[8], or 700,000 TB in decimal. With 20 TB drives, 1,000 TB takes fifty of them. The figures for other drives and for LTO tapes are in the TB to PB converter.

Arteon free tool screenshot: Convert petabytes to terabytes

Have a question or suggestion?

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