Base64 Encode and Decode Online

Base64 shows up in more places than most people realize: embedding an image directly inside HTML or CSS, sending binary data through APIs that only accept text, or reading the payload of a token that starts with eyJ. A Base64 encoder/decoder converts between the raw value and its Base64 text form in either direction, instantly.

What Base64 actually is

Base64 takes binary data — bytes — and re-represents it using only 64 printable characters (A–Z, a–z, 0–9, +, /). It doesn't compress or encrypt anything; it's purely a safe way to carry arbitrary bytes through systems (like text-based protocols, JSON, or URLs) that weren't designed to handle raw binary. That's why a Base64 string is always about a third longer than the original data — it's trading size for compatibility.

Where you'll actually run into it

• Data URIs — embedding a small image directly in HTML with <img src="data:image/png;base64,..."> instead of a separate file request.
• API authentication — Basic Auth headers send username:password Base64-encoded (not encrypted — it's reversible, so this only makes sense over HTTPS).
• Email attachments — MIME encodes binary attachments as Base64 so they survive being carried over text-only SMTP.
• Reading token payloads— a JWT's header and payload segments are Base64URL text you can decode to see the raw JSON underneath.

Encode vs. decode — knowing which you need

If you're starting from plain text or a file and need the Base64 form, you're encoding. If you've got a block of Base64 text and want to see what it actually says, you're decoding. It's easy to mix these up when you're moving quickly — the tool takes either direction, so a wrong guess costs you one click, not a re-paste.

How to encode or decode Base64

1. Open the Base64 Encoder/Decoder.
2. Paste your text (or Base64 string) and pick encode or decode.
3. The conversion runs instantly, entirely on your device — nothing is sent anywhere.
4. Copy the result.

A note on "security"

Base64 is encoding, not encryption. Anyone can decode it back to the original in one step — it provides zero confidentiality. If you need something that actually can't be read without a key, you want encryption or hashing, not Base64. For one-way fingerprints (checksums, password hashes), use the Hash Generatorinstead — hashing can't be reversed the way Base64 can.

Related developer tools

If what you're actually decoding is a URL-encoded string (percent signs, not Base64 characters), that's a different format — use URL Encoder/Decoderinstead. And once you've decoded a Base64 payload back into readable JSON, the JSON Formatter will make it readable.