What is Base64 and why do I need it?

Base64 is a way to represent binary data as text using 64 safe ASCII characters (A-Z, a-z, 0-9, +, /). It's needed for transmitting files and data through channels that only work with text: email protocols, JSON, XML, URL parameters, HTML attributes.

Is this encryption or data protection?

No. Base64 is encoding, not encryption. Anyone can decode a Base64 string back without a password or key. For protecting sensitive data, use real encryption (AES, RSA, etc.).

Why does file size increase after encoding?

Base64 uses 4 characters to encode every 3 bytes of data. This increases size by about 33%. For example, a 100 KB file becomes about 133 KB after encoding. This is the cost of text protocol compatibility.

What files can I encode?

Absolutely any: images (PNG, JPEG, GIF, SVG), documents (PDF, DOCX), archives, fonts, audio, video. Base64 works with any binary data. The only limit is size — up to 10 MB.

How do I embed an image in HTML using Base64?

Encode the image and use a Data URI: . This lets you embed small images directly in HTML without separate HTTP requests.

Is this tool safe to use?

Yes. Encoding is performed entirely in your browser using JavaScript. Data is not sent to servers or stored anywhere. You can verify this in your browser's developer tools.

Where is Base64 used in practice?

Email attachments (MIME), Data URIs in HTML/CSS, binary data in JSON APIs, storing images in databases, JWT tokens, embedding fonts in CSS, HTTP Basic authentication, and much more.

What's the difference between Base64 and Base64URL?

Standard Base64 uses + and / characters which have special meaning in URLs. Base64URL replaces them with - and _ respectively, and removes padding = characters. Use Base64URL for tokens, URL parameters, and filenames.

How does Base64 encoding affect website performance?

For small files (under 5 KB), Base64 speeds up loading by saving an HTTP request. For files over 10 KB, use regular links — browsers cache them more efficiently, and total traffic is lower without the 33% overhead.

Can I encode Cyrillic text and emojis?

Yes. The tool correctly handles UTF-8: Cyrillic, Chinese characters, emojis, and any Unicode symbols. Text is first converted to UTF-8 bytes, then encoded to Base64.

How do I use Base64 for Basic authentication?

Encode a string like "username:password" to Base64. Add the result to the HTTP header: Authorization: Basic ENCODED_STRING. Remember: this doesn't protect the password, it just encodes it for transmission.

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Base64 Encode

Base64 Encode

Convert text or files to Base64 format for safe transmission via email, API, JSON, or embedding in code. Instant processing right in your browser.

Decode Base64

When you need Base64 encoding

Sending files via API

REST and GraphQL APIs typically work with JSON, which doesn't support binary data directly. Base64 lets you send images, documents, or any file as a regular string in the request body.

Embedding resources in code

Small images, icons, and fonts can be encoded in Base64 and embedded directly in HTML or CSS. This reduces HTTP requests and speeds up page loading for small files.

How the Base64 algorithm works

Input data is split into groups of 3 bytes (24 bits). Each group is divided into 4 parts of 6 bits each. Every 6 bits are converted to one of 64 alphabet characters. If input isn't a multiple of 3 bytes, = characters are added for padding.

Web development applications

Data URIs for images and fonts in CSS, binary data transmission via WebSocket, file storage in browser localStorage, JWT token creation for authentication, file uploads via FormData in AJAX requests.

Optimization tip

Only embed files up to 5-10 KB via Base64. For larger images, use regular links — browsers cache them more efficiently than repeated Base64 strings in CSS or HTML.

How to encode data to Base64

Enter text or upload a file

Select the "Text" tab and enter your data, or upload a file via the "File" tab. Files up to 10 MB of any format are supported.

Start encoding

Click "Encode to Base64". Conversion happens instantly in your browser — no data is sent to our servers.

Copy or download result

Use the "Copy" button for clipboard or "Download" to save as a text file. The result is ready to use in your code or API.

Base64 Decode

Decode Base64 to original text or file in seconds. Auto-detects data type, instant browser...

Encoders

URL Encode

Encode text for safe use in URLs. Converts special characters, spaces, and non-ASCII chara...