Base64 Encoder / Decoder

Encode raw text strings into compliant Base64 format, or decode Base64 encoded characters back to plain text.

Encoding

How it works

A free utility to safely encode text into Base64 formats and decode Base64 strings back to UTF-8.

All calculations and formatting functions are performed directly in your local browser using standard JavaScript runtimes. Your input is not sent to our servers or stored on remote databases. Like the rest of developerOS, this page counts visits with Google Analytics and Vercel Analytics; they see the page you opened, never what you type into the tool. Privacy policy

Related tools

JWT Decoder

Decode JSON Web Tokens (JWT) client-side. Inspect the header, payload claims and signature segment. Decoding does not verify the signature.

Open tool

URL Encoder & Decoder

Encode plain text strings into URL-safe formats or decode escaped URL percent encodings.

Open tool

HTML Entity Encoder / Decoder

Encode text into HTML-safe entities, or decode named and numeric HTML entities back to plain text.

Open tool

About the Base64 Encoder / Decoder

Base64 turns arbitrary bytes into 64 printable ASCII characters so they can travel through text-only channels such as JSON fields, URLs, email and HTTP headers. This tool encodes text as UTF-8 first, so accented letters, CJK text and emoji round-trip correctly.

Choose URL-safe mode to swap + and / for - and _ and drop the = padding, which is the Base64URL form used in JWTs and URLs.

How to use it

Choose Encode Text or Decode Base64.
Type or paste the text; the result appears as you type.
Tick URL-Safe (Base64URL) if the result will go in a URL or a JWT, then press Copy Output.

Worked example

Encode Text mode, standard alphabet.

Input

Hello, World!

Result

SGVsbG8sIFdvcmxkIQ==

Common mistakes and gotchas

Base64 is an encoding, not encryption: anyone can decode it. Do not use it to hide secrets.
Encoded output is about one third larger than the input (every 3 bytes become 4 characters).
Decoding accepts both alphabets, tolerates line breaks and adds missing = padding. Paste only the Base64 part, not a data: URL prefix such as data:text/plain;base64,.
If the decoded bytes are not valid UTF-8 text (an image or a compressed file, for example) the tool says so instead of showing garbage; it decodes text, not files.

Frequently asked questions

What is the difference between Base64 and Base64URL?

Base64URL replaces + with - and / with _ and usually omits padding, so the result can sit in a URL or filename without percent-encoding.

Why does my decoded text look wrong?

The original bytes may use another character set than UTF-8, or the string may be a binary format. This tool always reads decoded bytes as UTF-8 text.

Is anything sent to a server?

No. Encoding and decoding use your browser's built-in functions on the text you type.

Related tools

Browse all 26 Toolkit tools

How it works

A free utility to safely encode text into Base64 formats and decode Base64 strings back to UTF-8.

About the Base64 Encoder / Decoder

Choose URL-safe mode to swap + and / for - and _ and drop the = padding, which is the Base64URL form used in JWTs and URLs.

Common mistakes and gotchas

Base64 is an encoding, not encryption: anyone can decode it. Do not use it to hide secrets.

Encoded output is about one third larger than the input (every 3 bytes become 4 characters).

Decoding accepts both alphabets, tolerates line breaks and adds missing = padding. Paste only the Base64 part, not a data: URL prefix such as data:text/plain;base64,.

If the decoded bytes are not valid UTF-8 text (an image or a compressed file, for example) the tool says so instead of showing garbage; it decodes text, not files.

Frequently asked questions

What is the difference between Base64 and Base64URL?

Base64URL replaces + with - and / with _ and usually omits padding, so the result can sit in a URL or filename without percent-encoding.

Why does my decoded text look wrong?

The original bytes may use another character set than UTF-8, or the string may be a binary format. This tool always reads decoded bytes as UTF-8 text.

Is anything sent to a server?

No. Encoding and decoding use your browser's built-in functions on the text you type.