Data Storage Converter

Convert between bytes, KB, MB, GB, TB, and PB in both binary (1024-based) and decimal (1000-based) systems.

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Understanding Data Storage Units

Data storage uses two measurement systems: decimal (base-10, used by storage manufacturers) and binary (base-2, used by operating systems). This is why a "1 TB" hard drive shows as approximately 931 GB in your OS.

Decimal vs Binary

Decimal (SI)	Value in Bytes	Binary (IEC)	Value in Bytes
1 KB	1,000	1 KiB	1,024
1 MB	1,000,000	1 MiB	1,048,576
1 GB	1,000,000,000	1 GiB	1,073,741,824
1 TB	1,000,000,000,000	1 TiB	1,099,511,627,776
1 PB	10¹⁵	1 PiB	2⁵⁰

Real-World Storage Examples

1 MB — A high-quality JPEG photo, a minute of MP3 audio
1 GB — About 250 MP3 songs, or 1 hour of SD video
1 TB — About 500 hours of HD video, or 250,000 photos
1 PB — About 500 billion pages of text, or 13.3 years of HD video

Frequently Asked Questions

Drive manufacturers use decimal (1 TB = 1,000,000,000,000 bytes), but your operating system uses binary (1 TiB = 1,099,511,627,776 bytes). So 1 TB — 1.0995 — 931 GiB, which is what your OS reports.

KB (kilobyte) = 1,000 bytes (decimal, SI standard). KiB (kibibyte) = 1,024 bytes (binary, IEC standard). The "bi" in KiB stands for "binary." Windows traditionally labels binary values as "KB" which causes confusion.

In decimal: 1 GB = 1,000 MB. In binary: 1 GiB = 1,024 MiB. Most consumer contexts (ISPs, storage) use the decimal definition.

Decimal vs. binary: the heart of every storage discrepancy

The reason a "1 TB" hard drive shows up in your operating system as 931 GB has nothing to do with reserved space or fraud. It is purely the difference between decimal-base and binary-base counting. Manufacturers count 1 TB as 1,000,000,000,000 bytes (10¹²). Most operating systems display sizes in binary, where 1 TiB = 1,099,511,627,776 bytes (2⁴⁰). Divide the decimal TB by 1.0995 to get the binary TiB figure, and the math lines up exactly.

Standard prefixes you should know in 2026

Decimal (SI): KB = 10³, MB = 10⁶, GB = 10⁹, TB = 10¹², PB = 10¹⁵, EB = 10¹⁸.
Binary (IEC): KiB = 2¹⁰, MiB = 2²⁰, GiB = 2³⁰, TiB = 2⁴⁰, PiB = 2⁵⁰.

Where each system is used

Hard-drive and SSD vendors use decimal. Network speed measurements use decimal (and bits, not bytes — a 100 Mbps link is 100,000,000 bits per second). RAM is sold in binary. Linux and macOS finder display in decimal-look binary numbers in newer versions; Windows still uses binary throughout. Cloud-storage pricing is decimal.

Bandwidth vs. storage gotcha

Bandwidth is measured in bits per second; storage in bytes. A 100 Mbps connection transfers about 12.5 MB per second under perfect conditions, because 1 byte = 8 bits. Real-world overhead from TCP, encryption, and packetisation typically reduces sustained throughput to 80–90% of the raw figure.