Base64 Encoder / Decoder / Validator

Encode, decode, and validate Base64 — text, files, images, and Data URLs. Everything runs in your browser

URL-safe Remove whitespace Remove padding Add padding Line break every 76 chars Output as Data URL

Input 0 chars

Samples:

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Drag & drop a file here, or click to browse

Max 25 MB

File: —

Type: —

Original size: —

Base64 size: —

Overhead: —

Raw Base64

Data URL

Large file detected. Processing may take a moment.

Base64 / Data URL Input 0 chars

Detected MIME: —

Decoded size: —

Input to Validate 0 chars

Paste a Base64 string and click Validate to see results.

All encoding, decoding, and validation happens in your browser. No data is sent to any server.

Tips

Base64 Is Not Encryption

Base64 is an encoding scheme, not encryption. Anyone can decode it instantly. Never use Base64 to protect sensitive data — use proper encryption instead.

Expect ~33% Size Increase

Base64 represents every 3 bytes of data as 4 characters. This means the encoded output is always about 33% larger than the original. Keep this in mind when embedding images or files.

URL-Safe Base64 for Web Use

Standard Base64 uses + and / which conflict with URLs. URL-safe Base64 replaces them with - and _, making it safe for query parameters, filenames, and JWT tokens.

Data URLs Embed Files Inline

A Data URL (data:[mime];base64,...) lets you embed images or files directly in HTML/CSS without separate HTTP requests. Great for small icons, but avoid it for large files due to the size overhead.

Common Use Cases

🔌

API Binary Data Transfer

Encode binary files like images, PDFs, or certificates into Base64 to safely include them in JSON API requests and responses.

🖼️

Inline Image Embedding

Convert small images to Data URLs and embed them directly in HTML or CSS, eliminating extra HTTP requests and speeding up page loads.

🔑

JWT Token Inspection

Decode the header and payload parts of JWT tokens to inspect claims, expiration times, and permissions without any external tool.

📧

Email Attachment Encoding

MIME email attachments are Base64-encoded. Decode them to recover the original file, or encode files for manual MIME construction.

⚙️

Configuration Value Verification

Kubernetes secrets, SSH keys, and many config files store values in Base64. Decode and validate them before deployment to catch errors early.

Frequently Asked Questions

What is Base64 encoding?

Base64 is a method of converting binary data into a text format using 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It is commonly used to transmit binary data over text-based protocols like HTTP, email, and JSON.

Is Base64 a form of encryption?

No. Base64 is encoding, not encryption. It provides no security whatsoever — anyone can decode it instantly. If you need to protect data, use proper encryption algorithms like AES.

Why does Base64 increase file size?

Base64 converts every 3 bytes into 4 characters, resulting in roughly 33% larger output. This is because it maps 6 bits per character instead of the full 8 bits per byte.

What are the = signs at the end?

The = characters are padding. Base64 works in groups of 3 bytes. If the input length is not a multiple of 3, one or two = signs are added to make the output length a multiple of 4.

What is a Data URL?

A Data URL has the format data:[mediatype];base64,[data]. It embeds the file content directly in HTML, CSS, or JavaScript, removing the need for a separate HTTP request. Best used for small assets like icons.

Is my data sent to any server?

No. All encoding, decoding, and validation happens entirely in your browser using JavaScript. Your data never leaves your device. You can verify this by disconnecting from the internet — the tool continues to work.