Character counts in kilobyte, or a megabyte or a gigabyte

Bytes (8 bits)
0.1 bytes: A single yes/no decision (actually 0.125 bytes, but I rounded)
1 byte: One character
2 bytes:
5 bytes
10 bytes: One word (a word of language, not a computer word)
20 bytes:
50 bytes:
100 bytes: Telegram; two punched computer (Hollerith) cards
200 bytes:
500 bytes:

Kilobyte 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
20 Kilobytes:
50 Kilobytes: Image of a document page, compressed
100 Kilobytes: Photograph, low-resolution
200 Kilobytes: Two boxes (4000) punched computer (Hollerith) cards
500 Kilobytes: Five boxes, one case (10,000 of punched computer (Hollerith) cards

Megabyte 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
500 Megabytes: CD-ROM

Gigabyte 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
10 Gigabytes:
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
200 Gigabytes: 50 Exabyte tapes

Terabyte 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 ligrary
10 Terabytes: Printed collection of the U. S. Library of Congress
50 Terabytes: Contents of a large mass storage system

Petabyte 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

Exabyte 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

Reference http://www.jamesshuggins.com/h/tek1/how_big.htm