💾 Data Storage Units Guide

Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and beyond. Understand the difference between SI (decimal) and binary (IEC) units.

Value

From unit

Real-World Context

1 KB ≈ Short email

A plain-text email without attachments. A few paragraphs of text. One second of low-bitrate audio.

1 MB ≈ JPEG photo

A compressed JPEG photo from a basic phone camera. A short MP3 clip. A Word document with images.

10 MB ≈ Song (MP3)

A 3–4 minute song at 320kbps MP3. A high-res photo from a DSLR. A short PDF with images.

1 GB ≈ Film (SD)

A standard-definition movie. About 200 MP3 songs. 1,000 JPEG photos. One hour of 1080p video (compressed).

1 TB ≈ Hard drive

A typical consumer hard drive. ~200,000 JPEG photos. ~200 HD films. About 17,000 hours of podcast audio.

1 PB ≈ Data centre rack

1,000 terabytes. All US academic research libraries ≈ 2 PB. A large social media platform stores hundreds of PB.

1 EB ≈ Internet traffic

1,000 petabytes. Global internet traffic was ~4.8 EB/month in 2022. The entire internet is estimated at ~40–100 ZB total.

1 ZB = 1 Zettabyte

10²¹ bytes. Total global data created in 2023 ≈ 120 ZB. The "digital universe" grows by tens of ZB per year.

⚠️ The SI vs binary confusion: Hard drive makers use SI (decimal): 1 TB = 1,000,000,000,000 bytes. Operating systems use binary: 1 TiB = 1,099,511,627,776 bytes. A "1 TB" drive shows as ~931 GiB in Windows. This is why your drive always seems smaller than advertised — it's a labelling convention difference, not missing space.

📡 Bits vs bytes in networking: Network speeds are measured in bits per second (bps). Storage is in bytes. 100 Mbps internet = 12.5 MB/s actual download speed (divide by 8). A "gigabit" internet connection = 125 MB/s theoretical max. ISPs advertise in bits; download managers show bytes.