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Base64 Encode

Encode any text to Base64 instantly — UTF-8 safe, emoji supported. Free, fast, no sign-up.

Last updated: October 2026

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How Base64 encoding works

Text is converted to its UTF-8 bytes.
Bytes are split into groups of 3 (24 bits).
Each group becomes 4 Base64 characters (6 bits each); '=' pads the end.

Example: "Hi" → 48 69 → SGk=.

Background reading: the Base64 encoding scheme on Wikipedia.

Base64 alphabet

The 64 characters of the Base64 alphabet and their 6-bit values (0–63).

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

Base64 encoding in code

Python

import base64
base64.b64encode("Hi 👋".encode()).decode()
# → 'SGkg8J+Riw=='

JavaScript

btoa(unescape(encodeURIComponent("Hi 👋")));
// → 'SGkg8J+Riw=='

C

/* C has no standard-library Base64. The usual approach:
   1. Take the 64-character alphabet:
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
   2. Split the input bytes into 6-bit groups; each group (0-63)
      is an index into the alphabet.
   3. Every 3 input bytes become 4 output characters; pad the
      final group with '='. Example: "Hi" -> 0x48 0x69
      -> 6-bit groups 18, 6, 36 -> "SGk=". */

Common values

“Hi” → SGk=
“Man” → TWFu
“A” → QQ==
“AB” → QUI=
empty string → empty string

Key takeaways

Base64 packs 3 bytes into 4 ASCII characters — output grows about 33%.
The alphabet is A–Z, a–z, 0–9, +, / with = padding.
It is an encoding, not encryption — anyone can decode it.
Use the URL-safe variant (– and _) inside URLs.

Frequently asked questions

What is Base64?

Base64 turns binary data into plain ASCII text using 64 safe characters — handy for embedding data in JSON, URLs and emails.

Does it support emoji?

Yes — the encoder is UTF-8 safe, so emoji and non-Latin scripts encode correctly.

Is Base64 encryption?

No — anyone can decode it. It encodes data for transport, it doesn't protect it.

Why does Base64 output end with =?

= is padding — it fills the last 4-character group when the input is not a multiple of 3 bytes.

How much bigger is Base64 than the original?

About 33% bigger — every 3 bytes become 4 characters.

What characters are used in Base64?

A–Z, a–z, 0–9, + and / (64 total), plus = for padding. See the alphabet table above.

Is Base64 safe for URLs?

Standard Base64 is not — + and / have special meaning in URLs. URL-safe Base64 swaps them for – and _.

Need to decode? Try our Base64 decoder.

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

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