Kilobyte to Terabyte

In the SI decimal system (used by storage manufacturers), 1 kB = 1,000 bytes. In the older binary convention (used by operating systems and programrs), what was called a "kilobyte" was actually 1,024 bytes — now formally called a kibibyte (KiB). The IEC standardized the KiB prefix in 1998 to eliminate this ambiguity. Modern OS versions (Windows Vista+, macOS 10.6+) increasingly use the correct IEC binary prefixes for displayed values.

One kilobyte (1,000 bytes) can store approximately 1,000 ASCII characters, roughly half a page of plain text, or about 140–170 words. With UTF-8 encoding, common English text is still close to 1 byte per character. A full page of formatted text with some HTML markup is typically 3–6 kB.

Storage manufacturers measure 1 kB = 1,000 bytes (decimal). Operating systems traditionally reported 1 kB = 1,024 bytes (binary). A drive advertised as 1 TB (1,000,000,000,000 bytes by the manufacturer) shows as approximately 931 GiB in Windows — not a lie, but a different counting system. The IEC binary prefixes (KiB, MiB, GiB) were introduced in 1998 to clarify this, and most modern OSes now use them correctly.

Files under 1 MB are typically measured in kilobytes: text files (1–100 kB), favicons and tiny images (1–50 kB), simple HTML pages (10–200 kB), audio samples (under 1 second of compressed audio), configuration and log files. Once files exceed a few hundred kilobytes they are more conveniently expressed in megabytes.

Early email systems in the 1980s–90s imposed attachment limits of 50–100 kB due to tiny disk quotas and slow dial-up links. As infrastructure improved, limits rose: most modern email providers (Gmail, Outlook) cap attachments at 25 MB. The limits persist because email traverses multiple relay servers (MTAs), each with its own size constraint, and Base64 encoding inflates binary attachments by ~33%. Some corporate and government systems still enforce 5–10 MB limits for security scanning and archival compliance. For larger files, email providers redirect to cloud links (Google Drive, OneDrive) rather than raising the attachment ceiling.

1 terabyte (TB) = 1,000 gigabytes (GB) in the SI decimal system. In the binary IEC system, 1 tebibyte (TiB) = 1,024 gibibytes (GiB). Consumer hard drives and SSDs are labelled in decimal TB; operating systems may display available space in either GB or GiB depending on the OS and version, leading to a discrepancy of up to ~7% between the label and the OS display.

A 1 TB SSD holds approximately: 200,000 JPEG photos (at 5 MB each), 250 HD movies (at 4 GB each), 200+ modern AAA games (at 50 GB average), or enough for about 100 hours of 4K video footage from a modern camera. In practice, the OS and drive firmware overhead reduce usable capacity to roughly 900–930 GB as reported by the operating system.

A terabyte (TB) = 10¹² bytes = 1,000,000,000,000 bytes. A tebibyte (TiB) = 2⁴⁰ bytes = 1,099,511,627,776 bytes. The TiB is about 9.95% larger. This gap is why a 1 TB hard drive appears as 931 GiB (≈ 0.909 TiB) in Windows. The IEC formally defined TiB in 1998 to eliminate this naming ambiguity.

Timeline depends heavily on use case: continuous 4K video recording fills 1 TB in about 2–3 hours (at 1 GB/min). Typical laptop use (documents, photos, apps) might take 3–5 years to fill 1 TB. A game library of 20 modern AAA titles uses 500 GB–1 TB. Home security camera systems recording 24/7 at 1080p use about 1 TB every 10–15 days per camera.

For most individuals, 1 TB of cloud storage is generous: it holds 200,000+ photos, years of documents, and even video libraries. Google One offers 2 TB for €9.99/month; iCloud offers 2 TB for £6.99/month. Power users — especially photographers and videographers — may need 2–5 TB. Family sharing plans can make 2 TB cost-effective across multiple users.