Data Storage Converter

Convert between data storage units showing both the decimal standard (KB = 1000 bytes) and the binary standard (KiB = 1024 bytes) side by side. See exactly why a 1 TB drive shows about 931 GB on your computer.
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Input
KB = 1000 B (decimal) · KiB = 1024 B (binary). Hard drives use decimal; operating systems mostly report binary.
Data Storage Conversion
Entered as1 TB
Exact byte count1.00 TB (1,000,000,000,000 B)
Decimal standard
KB1,000,000,000
MB1,000,000
GB1,000
TB1
PB0
Binary standard
KiB976,562,500
MiB953,674.32
GiB931.32
TiB0.91
PiB0
Sold as 1 TB (decimal), a Windows/Linux disk will report about 931.32 GiB— that is why the "capacity" never matches the label.
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Overview

The Data Storage Converter shows data sizes in every common unit using both the decimal standard (KB = 1000 bytes) and the binary standard (KiB = 1024 bytes) at the same time. It explains the classic mismatch where a drive sold as 1 TB reports roughly 931 GB on a computer.

Common Use Cases

How to Use

1
Type the storage size and pick its unit from the dropdown (B, KB, MB, GB, TB, PB, KiB, MiB, GiB, TiB, PiB).
2
The exact byte count is shown first.
3
The Decimal standard table lists values where KB = 1000 bytes, and the Binary standard table where KiB = 1024 bytes.
4
Use the Print button to export the conversion table.

Example Scenario

Why does my 1 TB drive show 931 GB?

Enter 1 with unit TB. The calculator shows 1,000,000,000,000 bytes in the decimal table, but the binary table reports 909.49 GiB (about 931.32 GB in decimal labels) — exactly what Windows and Linux report. Drives are sold in decimal units while operating systems usually count in binary.

Technical Notes

Decimal units multiply by 1000 (KB, MB, GB, TB, PB). Binary units multiply by 1024 (KiB, MiB, GiB, TiB, PiB).

Hard drive vendors advertise decimal capacity. Operating systems often report storage in binary units but label them with decimal names, which produces the smaller number.

The exact byte count is the ground truth; every table value is derived from it, so decimal and binary columns always agree with each other.

Common Mistakes

Frequently Asked Questions

Vendors sell drives in decimal units (1 TB = 1,000,000,000,000 bytes), while Windows and Linux commonly report in binary units (GiB) and round the number. The binary table shows the exact figures.

GB is decimal (1 GB = 1,000,000,000 bytes). GiB is binary (1 GiB = 1,073,741,824 bytes). They differ by about 7.3%.

Divide the decimal value by 1.073741824. For example, 1000 GB = 931.32 GiB.

macOS reports storage in decimal units since OS X 10.6, so its numbers usually match the drive label. Windows and most Linux file managers report in binary.

Related Topics

Kilobyte vs kibibyteStorage unitsBinary vs decimalHard drive capacityData storageCloud storage