Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 strings. Fully client-side — nothing leaves your browser.
Output will appear here...What Is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using only 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It was designed to safely transmit binary data — images, files, audio — over systems that only handle plain text, such as email protocols and HTTP headers.
Every 3 bytes of input become exactly 4 Base64 characters. This increases data size by about 33%, which is the small tradeoff for encoding reliability. Base64 is not compression — it is a representation change.
When Do Developers Use Base64?
Embedding Images in CSS and HTML
Instead of linking to an external image file (which requires an HTTP request), you can embed the image directly in CSS or HTML as a Base64 data URI: url("data:image/png;base64,iVBOR..."). This technique eliminates a network round-trip and is commonly used for small icons and critical above-the-fold images.
Sending Binary Data in JSON APIs
JSON only supports text values. When an API needs to return or accept binary data — images, PDF files, audio clips — Base64 encoding wraps the binary as a text string that JSON can carry safely.
HTTP Basic Authentication Headers
HTTP Basic Auth encodes username:password in Base64 and sends it in the Authorization header. Use this decoder to inspect auth headers during API debugging — though remember, Base64 is not encryption.
JWT Token Components
The header and payload sections of a JWT token are Base64URL-encoded. You can decode any JWT payload with this tool to inspect the claims, expiry, and algorithm without needing the signing secret. For a dedicated JWT experience, try our JWT Decoder.
Email Attachments (MIME)
Email protocols such as SMTP are text-only. Email clients encode file attachments in Base64 before transmission and decode them on the receiving end. This is handled transparently by email clients but understanding Base64 helps when debugging raw MIME messages.
How to Use This Base64 Tool
- To encode: Type or paste text in the input field → Click Encode → Copy the Base64 output
- To decode: Paste a Base64 string → Click Decode → See the original text
- The tool handles Unicode and UTF-8 correctly, including Hindi, Arabic, Chinese, and emoji characters
Frequently Asked Questions
Is Base64 the same as encryption?
No. Base64 is encoding, not encryption. It is trivially reversible — anyone with the Base64 string can decode it back to the original. Never use Base64 to secure sensitive data.
What is Base64 used for?
Base64 is used to safely transmit binary data over text-based systems. Common uses include embedding images in HTML/CSS as data URIs, sending binary data in JSON APIs, HTTP Basic Authentication headers, and JWT token components.
What is the difference between Base64 and Base64URL?
Standard Base64 uses + and / characters which have special meaning in URLs. Base64URL replaces them with - and _ for safe use in URLs, filenames, and HTTP headers.
Why does my Base64 string end with == ?
The = characters are padding. Base64 encodes 3 bytes at a time. If the input length is not divisible by 3, = signs pad the output to a multiple of 4 characters.
Does this tool handle Unicode and special characters?
Yes. The tool correctly handles UTF-8 text including emojis, Hindi, Chinese, Arabic, and other non-ASCII characters — unlike some tools that break on non-ASCII input.
Is my data sent to any server when using this tool?
No. All encoding and decoding happens in your browser using JavaScript. No data is ever transmitted, logged, or stored anywhere.