Base 62

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Numeral systems by culture
Hindu-Arabic numerals
Indian Eastern Arabic Khmer	Indian family Brahmi Thai
East Asian numerals
Chinese Counting rods	Japanese Korean
Alphabetic numerals
Abjad Armenian Cyrillic Ge'ez	Hebrew Greek (Ionian) Āryabhaṭa
Other systems
Attic Babylonian Egyptian Etruscan	Mayan Roman Urnfield
List of numeral system topics
Positional systems by base
Decimal (10)
2, 4, 8, 16, 32, 64
1, 3, 9, 12, 20, 24, 30, 36, 60, more…
v • d • e

Base 62 is a positional notation using a base of 62. The twenty-six uppercase letters A-Z, twenty-six lowercase letters a-z and ten digits 0-9 can be used to provide the 62 separate symbols needed.

[edit] Advantages

When a large number is going to be logged using ASCII characters, Base 62 allows for very large numbers to be described in significantly fewer characters. A prime example of this is UNIX time stamps.

Base 62 numbers can also be included in a URL without encoding any characters.

[edit] Base 62 alphabet

It uses an alphabet of 0–9, followed by A–Z, followed by a–z (thus "A" actually has a numerical value of 10).

The Base 62 alphabet

Value	Symbol	Value	Symbol	Value	Symbol	Value	Symbol	Value	Symbol	Value	Symbol	Value	Symbol
0	0	9	9	18	I	27	R	36	a	45	j	54	s
1	1	10	A	19	J	28	S	37	b	46	k	55	t
2	2	11	B	20	K	29	T	38	c	47	l	56	u
3	3	12	C	21	L	30	U	39	d	48	m	57	v
4	4	13	D	22	M	31	V	40	e	49	n	58	w
5	5	14	E	23	N	32	W	41	f	50	o	59	x
6	6	15	F	24	O	33	X	42	g	51	p	60	y
7	7	16	G	25	P	34	Y	43	h	52	q	61	z
8	8	17	H	26	Q	35	Z	44	i	53	r