Is Base64 encryption?

No. Base64 is reversible encoding with no secret key. Anyone with the string can decode it.

What is the difference between standard and URL-safe Base64?

Standard Base64 uses + and / and often ends with = padding. URL-safe Base64 (RFC 4648 §5) uses - and _ instead and usually omits padding so the value can sit in query strings or path segments.

Why does decoding fail with a padding or alphabet error?

Strict decoders expect a matching alphabet and valid length. Missing = padding, mixed +/ with -_, or truncated strings are common causes. Try the matching Standard or URL-safe mode, or add padding until the length is a multiple of four.

Can I encode an image file here?

This tool is for UTF-8 text. For image files and data URIs, use the Image to Base64 tool instead.

Base64 Encoder & Decoder

Encode or decode UTF-8 text as standard or URL-safe Base64. Useful for API payloads, Basic Auth debugging, and data snippets.

This conversion runs only in your browser — nothing is uploaded.

URL-safe

URL-safe uses - and _ instead of + and /, and omits = padding.

Input0
Output0
OptionsStandard

Input

Output

For image files, use Image to Base64 — Data URI Encoder

What is this tool?

This Base64 encoder and decoder converts between UTF-8 text and Base64. Choose Standard (+/ with = padding) or URL-safe (-_ without padding) depending on where the value will be used.

Base64 is encoding, not encryption: there is no secret key, and anyone can reverse the string. Output is about one-third larger than the input because every three bytes become four ASCII characters.

Use it for text payloads, Basic Auth debugging, and short data snippets. It is not a file encoder—use Image to Base64 for binary images and data URIs.

Common use cases

Prepare or inspect Base64 fields in API JSON bodies and headers
Build or decode the credential part of an HTTP Authorization: Basic … header
Encode short text for data-URI style snippets (text only; images belong on Image to Base64)

How to use

Choose Encode or Decode. Conversion updates live as you type.
Toggle URL-safe when the value must use -_ and omit = padding.
Paste UTF-8 text (encode) or a Base64 string (decode). Whitespace in Base64 input is ignored.
Copy the output. If decode fails, match Standard vs URL-safe and check padding or truncation.

Examples

Input / setting	Output	Notes
`Hello` → Standard encode	`SGVsbG8=`	Classic UTF-8 sample with padding.
`SGVsbG8=` → Decode	`Hello`	Round-trip of the sample above.
`user:pass` → Standard encode	`dXNlcjpwYXNz`	Credential blob before a Basic Auth header.
`subjects?_d` → URL-safe encode	`c3ViamVjdHM_X2Q`	Uses `_` instead of `/` and omits `=` (edge vs standard).

Practical pitfalls

Base64 is not encryption or access control—treat encoded secrets as still exposed.
Mixing alphabets breaks consumers: a JWT-style URL-safe string will fail many “standard only” decoders if you leave -_ or strip padding incorrectly.
This page encodes text, not arbitrary files; large binaries belong in Image to Base64 or offline tooling.

References

Last reviewed: 2026-07-26

Frequently asked questions

Is Base64 encryption?: No. Base64 is reversible encoding with no secret key. Anyone with the string can decode it.
What is the difference between standard and URL-safe Base64?: Standard Base64 uses + and / and often ends with = padding. URL-safe Base64 (RFC 4648 §5) uses - and _ instead and usually omits padding so the value can sit in query strings or path segments.
Why does decoding fail with a padding or alphabet error?: Strict decoders expect a matching alphabet and valid length. Missing = padding, mixed +/ with -_, or truncated strings are common causes. Try the matching Standard or URL-safe mode, or add padding until the length is a multiple of four.
Can I encode an image file here?: This tool is for UTF-8 text. For image files and data URIs, use the Image to Base64 tool instead.