Whenever we discuss quantities of data, we tend to do it in the abstract. We speak of a kilobyte, or a megabyte or a gigabyte without really knowing what it represents.
The following table shows various quantities of bytes, in each power of ten. Usually, they are shown with multiples of 2 and 5 also. For example, 1 Kilobyte, 2 Kilobytes, 5 Kilobytes. All the examples are approximate and are rounded.
Bytes (8 bits)
- 0.1 bytes: A single yes/no decision (actually 0.125 bytes, but I rounded)
- 1 byte: One character
- 10 bytes: One word (a word of language, not a computer word)
- 100 bytes: Telegram; two punched computer (Hollerith) cards
Kilobytes
1,024 bytes; 210; approx. 1,000 or 103.
- 1 Kilobyte: Joke; (very) short story
- 2 Kilobytes: Typewritten page
- 10 Kilobytes: Page out of an encyclopedia
- 50 Kilobytes: Image of a document page, compressed
- 100 Kilobytes: Photograph, low-resolution
- 200 Kilobytes: Two boxes (4000) punched computer (Hollerith) cards
Megabytes
1,048,576 bytes; 220; approx 1,000,000 or 106.
- 1 Megabyte: Small novel; 3-1/2 inch diskette
- 2 Megabytes: Photograph, high resolution
- 5 Megabytes: Complete works of Shakespeare; 30 seconds of broadcast-quality video
- 10 Megabytes: Minute of high-fidelity sound; digital chest X-ray; Box of 3-1/2 inch diskettes
- 20 Megabytes: Two boxes of 3-1/2 inch diskettes
- 50 Megabytes: Digital mammogram
- 100 Megabytes: Yard of books on a shelf; two encyclopedia volumes
- 200 Megabytes: Reel of 9-track tape; IBM 3480 cartridge tape
- 700 Megabytes: CD-ROM, a DVDRip.
Gigabytes
1,073,741,824 bytes; 230; approx 1,000,000,000 or 109.
- 1 Gigabyte: Paper in the bed of a pickup; symphony in high-fidelity sound; broadcast quality movie
- 2 Gigabytes: 20 yards of books on a shelf
- 5 Gigabytes: 8mm Exabyte tale
- 20 Gigabytes: Audio collection of the works of Beethoven; five Exabyte tapes; VHS tape used to store digital data
- 50 Gigabytes: Library floor of books on shelves
- 100 Gigabytes: Library floor of academic journals on shelves; large ID-1 digital tape
Terabytes
1,099,511,627,776 or 240; approx. 1,000,000,000,000 or 1012.
- 1 Terabyte: Automated tape robot; all the X-ray films in a large technological hospital; 50,000 trees made into paper and printed; daily rate of EOS (Earth Orbiting System) data (1998)
- 2 Terabytes: Academic research library
- 10 Terabytes: Printed collection of the U. S. Library of Congress
- 50 Terabytes: Contents of a large mass storage system
Petabytes
1,125,899,906,842,624 bytes or 250, approx. 1,000,000,000,000,000 or 1015.
- 1 Petabyte: 3 years of EOS data (2001)
- 2 Petabytes: All U. S. academic research libraries
- 20 Petabytes: 1995 production of hard-disk drives
- 200 Petabytes: All printed material; 1995 production of digital magnetic tape
Exabytes
1,152,921,504,606,846,976 bytes or 260, approx. 1,000,000,000,000,000,000 or 1018.
- 5 Exabytes: All words ever spoken by human beings.
Zettabyte
1,180,591,620,717,411,303,424 bytes or 270, approx. 1,000,000,000,000,000,000,000 or 1021
Yottabyte
1,208,925,819,614,629,174,706,176 bytes or 280, approx. 1,000,000,000,000,000,000,000,000 or 1024