Petabyte to Megabyte

1 petabyte (PB) = 1,000 terabytes (TB) in the SI decimal system. In the binary IEC system, 1 pebibyte (PiB) = 1,024 tebibytes (TiB) = 1,125,899,906,842,624 bytes. The distinction matters for enterprise storage procurement: a petabyte of raw disk capacity appears as about 909 TiB in an OS reporting binary units.

Petabyte-scale storage is common at: social media platforms (Facebook/Meta stores over 100 PB of photos alone), streaming services (Netflix's content library is estimated at 100+ PB), government agencies (US NSA, CERN particle physics data), genomic research institutions, and large financial exchanges storing tick-level trading data. Major cloud providers (AWS, Azure, GCP) collectively store zettabytes.

In 2024, cloud storage costs roughly $20–25 per TB per month (S3 standard tier), making 1 PB approximately $20,000–$25,000/month. Raw enterprise disk hardware for 1 PB runs about $20,000–$50,000 upfront (at $20–50 per TB for high-density drives), plus ongoing power, cooling, and management overhead. Tape-based archival storage is considerably cheaper at $2–5 per TB.

YouTube users upload approximately 500 hours of video per minute, or 720,000 hours per day. At an average compressed size of 1–2 GB per hour of HD video, that equates to roughly 720–1,440 TB (0.7–1.4 PB) of new video data per day — before YouTube re-encodes into multiple formats and quality levels, which multiplies storage requirements several-fold.

The SI prefix hierarchy above petabyte: exabyte (EB, 10¹⁸ bytes), zettabyte (ZB, 10²¹ bytes), yottabyte (YB, 10²⁴ bytes), ronnabyte (RB, 10²⁷ bytes), and quettabyte (QB, 10³⁰ bytes) — the last two added by the BIPM in 2022. Current global data storage is estimated in the hundreds of exabytes; no single organisation approaches yottabyte scale.

A JPEG photo from a modern smartphone is typically 3–8 MB depending on resolution and compression settings. A RAW format photo from a DSLR or mirrorless camera is 20–50 MB per shot. A PNG screenshot at full HD (1920×1080) is about 1–3 MB; a compressed JPEG screenshot may be under 200 kB.

Video data usage depends heavily on quality: SD video uses roughly 700 MB per hour; HD (1080p) uses 1.5–3 GB per hour; 4K uses 7–20 GB per hour. These are byte-based measurements. In terms of bitrate: SD ≈ 1.5 Mbps, HD ≈ 5–8 Mbps, 4K ≈ 15–25 Mbps — where the "b" is bits, requiring division by 8 to convert to MB/s.

Compression algorithms like ZIP, GZIP, and ZSTD find and eliminate redundancy in data. Typical ratios vary dramatically by file type: plain text compresses to 20–30% of original size (a 10 MB log file becomes 2–3 MB); source code compresses to 25–35%; office documents (DOCX, XLSX) are already ZIP-compressed internally, so re-compressing gains little. JPEG, MP3, and H.264 video are already lossy-compressed and typically shrink by less than 5% with ZIP. A 100 MB folder of mixed files typically compresses to 40–60 MB. The key principle: compression removes statistical redundancy, so already-compressed or random data cannot be reduced further.

MB (megabyte) = 1,000,000 bytes (SI decimal). MiB (mebibyte) = 1,048,576 bytes (IEC binary). The difference is about 4.9%. Windows historically displayed storage in binary units but labelled them as "MB" — confusingly. Since Windows Vista, Microsoft has used the binary calculation consistently. macOS switched to SI decimal units in OS X 10.6 Snow Leopard (2009), matching the way hard drive manufacturers measure capacity.

Approximate data consumption per hour: web browsing = 60–100 MB, social media scrolling = 100–300 MB, music streaming (Spotify standard) = 40–50 MB, video calls (Zoom standard quality) = 300–500 MB, YouTube HD = 1,500–3,000 MB. These are rough averages and vary by content, settings, and network conditions.