Base64 Encoding & Decoding

Introduction to Base64

Base64 is an encoding scheme used to represent binary data in an ASCII string format by translating it into a radix-64 representation. It is commonly used to encode data for safe transmission over text-based protocols (like email or HTTP) where binary data might otherwise be corrupted or misinterpreted.

Base64 encoding takes 3 bytes of binary data (24 bits) and splits them into four 6-bit groups. Each 6-bit group is mapped to a character in the Base64 alphabet. If the data doesn't divide evenly into 3-byte chunks, padding (=) is added to make it a multiple of 4 characters.

Base64 Encoding Table

Value	Character	Value	Character	Value	Character	Value	Character
0	A	1	B	2	C	3	D
4	E	5	F	6	G	7	H
8	I	9	J	10	K	11	L
12	M	13	N	14	O	15	P
16	Q	17	R	18	S	19	T
20	U	21	V	22	W	23	X
24	Y	25	Z	26	a	27	b
28	c	29	d	30	e	31	f
32	g	33	h	34	i	35	j
36	k	37	l	38	m	39	n
40	o	41	p	42	q	43	r
44	s	45	t	46	u	47	v
48	w	49	x	50	y	51	z
52	0	53	1	54	2	55	3
56	4	57	5	58	6	59	7
60	8	61	9	62	+	63	/

Padding

If the input has 1 extra byte after grouping into sets of 3, = is added at the end.
If the input has 2 extra bytes, == is added.

Example

Input (ASCII): Man

Binary: 01001101 01100001 01101110
Grouped into 6 bits: 010011 010110 000101 101110
Base64: TWFu

Value	Character	Value	Character	Value	Character	Value	Character
0	A	1	B	2	C	3	D
4	E	5	F	6	G	7	H
8	I	9	J	10	K	11	L
12	M	13	N	14	O	15	P
16	Q	17	R	18	S	19	T
20	U	21	V	22	W	23	X
24	Y	25	Z	26	a	27	b
28	c	29	d	30	e	31	f
32	g	33	h	34	i	35	j
36	k	37	l	38	m	39	n
40	o	41	p	42	q	43	r
44	s	45	t	46	u	47	v
48	w	49	x	50	y	51	z
52	0	53	1	54	2	55	3
56	4	57	5	58	6	59	7
60	8	61	9	62	+	63	/

Value	Character	Value	Character	Value	Character	Value	Character
0	A	1	B	2	C	3	D
4	E	5	F	6	G	7	H
8	I	9	J	10	K	11	L
12	M	13	N	14	O	15	P
16	Q	17	R	18	S	19	T
20	U	21	V	22	W	23	X
24	Y	25	Z	26	a	27	b
28	c	29	d	30	e	31	f
32	g	33	h	34	i	35	j
36	k	37	l	38	m	39	n
40	o	41	p	42	q	43	r
44	s	45	t	46	u	47	v
48	w	49	x	50	y	51	z
52	0	53	1	54	2	55	3
56	4	57	5	58	6	59	7
60	8	61	9	62	+	63	/

Value	Character	Value	Character	Value	Character	Value	Character
0	A	1	B	2	C	3	D
4	E	5	F	6	G	7	H
8	I	9	J	10	K	11	L
12	M	13	N	14	O	15	P
16	Q	17	R	18	S	19	T
20	U	21	V	22	W	23	X
24	Y	25	Z	26	a	27	b
28	c	29	d	30	e	31	f
32	g	33	h	34	i	35	j
36	k	37	l	38	m	39	n
40	o	41	p	42	q	43	r
44	s	45	t	46	u	47	v
48	w	49	x	50	y	51	z
52	0	53	1	54	2	55	3
56	4	57	5	58	6	59	7
60	8	61	9	62	+	63	/