Data Size Converter

The Binary vs Decimal Confusion

A kilobyte is either 1,000 bytes or 1,024 bytes depending on who you ask, and this ambiguity has confused computer users for decades. Storage manufacturers use the decimal definition (1 KB = 1,000 bytes, 1 GB = 1,000,000,000 bytes), making their drives appear larger on the packaging. Operating systems historically used the binary definition (1 KB = 1,024 bytes, 1 GB = 1,073,741,824 bytes), making the same drive appear smaller once you plug it in. A hard drive labeled "500 GB" by the manufacturer shows as approximately 465 GB in Windows because Windows reports binary gigabytes. This is not missing space or a scam - it is a labeling inconsistency. The converter above handles both systems and shows the conversion clearly so you always know which definition is being used.

IEC Units: The Attempt at Clarity

The International Electrotechnical Commission introduced unambiguous binary prefixes in 1998 to resolve the confusion: kibibyte (KiB) = 1,024 bytes, mebibyte (MiB) = 1,048,576 bytes, gibibyte (GiB) = 1,073,741,824 bytes, tebibyte (TiB) = 1,099,511,627,776 bytes. Under this system, "kilobyte" (KB) means exactly 1,000 bytes with no ambiguity. Linux adopted these units in many command-line tools (ls -lh shows decimal, but du can show either). macOS switched to decimal kilobytes and gigabytes in Snow Leopard (2009). Windows still displays "GB" meaning GiB, perpetuating the confusion for most users. The converter supports both naming conventions and shows conversions in both systems simultaneously so you can communicate precisely regardless of which convention your audience uses.

Quick Reference for Common File Sizes

A plain text email without attachments: 5-50 KB. A typical web page (HTML, CSS, JS): 2-5 MB total. A smartphone photo at 12 megapixels: 3-5 MB (JPEG) or 12-25 MB (RAW/HEIC). A minute of MP3 audio at 320 kbps: approximately 2.4 MB. A minute of FLAC lossless audio: approximately 30 MB. A minute of 1080p H.264 video: 100-200 MB. A minute of 4K H.265 video: 200-400 MB. A full Blu-ray movie: 25-50 GB. A modern AAA game installation: 50-150 GB. An uncompressed operating system backup: 20-50 GB. The entire English Wikipedia (text only, compressed): approximately 22 GB. The entire Library of Congress digitized collection: approximately 15 petabytes. These reference points help estimate storage needs, transfer times, and bandwidth requirements for capacity planning and infrastructure decisions.

Transfer Time Calculations

Network speeds are measured in bits per second, but file sizes are measured in bytes. Since 1 byte equals 8 bits, a 100 Mbps (megabit) connection transfers approximately 12.5 MB (megabytes) per second under ideal conditions. Real-world overhead from protocol headers, TCP congestion control, encryption (TLS), router latency, and shared bandwidth typically reduces effective throughput to 70-90% of the theoretical maximum. Downloading a 1 GB file on a 100 Mbps connection takes roughly 80-100 seconds in practice, not the 80 seconds that raw division suggests. WiFi connections experience additional overhead from the wireless protocol, signal quality, channel congestion, and distance from the access point, often achieving 50-70% of the advertised link speed.

Storage Unit Progression

Byte (B): a single character of ASCII text. Kilobyte (KB): a short email or a small text file. Megabyte (MB): a high-resolution photograph or a minute of compressed audio. Gigabyte (GB): a feature-length movie in standard definition or about 250 MP3 songs. Terabyte (TB): roughly 500 hours of HD video or 250,000 photos. Petabyte (PB): 1,000 terabytes, approximately 500 billion pages of printed text. Exabyte (EB): 1,000 petabytes, roughly the amount of data the entire internet generated daily in 2020. Zettabyte (ZB): 1,000 exabytes, the approximate total amount of data existing worldwide. Yottabyte (YB): 1,000 zettabytes, a unit that exists mathematically but has no current practical application because nothing stores or generates this much data. The converter handles all of these units in both binary and decimal systems.

Frequently asked questions