Base64 Encoder & Decoder: Encode and Decode Any Text or File
Base64 encoding is everywhere in web development — authentication tokens, email attachments, data URIs for images, JWT payloads, and API credentials. Formly's Base64 tool lets you encode any text or file and decode any Base64 string instantly, with no data leaving your browser.
Try Base64 Encoder/Decoder Free →What Is Base64 and Why Is It Used?
Base64 is an encoding scheme that converts binary data to ASCII text using a 64-character alphabet (A–Z, a–z, 0–9, +, /). It's used when you need to transmit binary data through systems designed for text — like email (MIME encoding), HTML (data: URIs), or HTTP headers. Base64 is encoding, not encryption — it provides no security.
Common Base64 Use Cases
Embedding images in HTML/CSS as data URIs (no separate HTTP request). Encoding API credentials for HTTP Basic Authentication. Storing binary data in JSON (which only supports text). JWT (JSON Web Tokens) encode header and payload sections in Base64. Email attachments are Base64-encoded in the MIME standard.
Base64 Encoding vs URL-Safe Base64
Standard Base64 uses +, / and = padding which can conflict with URL characters. URL-safe Base64 (Base64URL) replaces + with - and / with _ and omits padding. JWTs use URL-safe Base64. The encoder supports both variants.
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Decoding Base64: What You See
Decoding a Base64 string reveals the original binary content. For text, this is readable. For images or binary files, you'll see unreadable binary data. The tool handles both — for Base64-encoded images, it can render the decoded image directly.
Base64 and Security
Base64 is frequently confused with encryption. It provides absolutely no security — anyone who sees the Base64 string can decode it instantly. Never use Base64 to "hide" passwords or sensitive data. For security, use proper encryption (AES, RSA) or hashing (bcrypt, SHA-256).
File Size Impact
Base64 encoding increases file size by approximately 33% because 3 bytes of binary data become 4 bytes of ASCII text. This is a trade-off: you gain compatibility at the cost of size. For large files, this overhead is significant — a 1MB image becomes ~1.37MB as Base64.
Frequently Asked Questions
Is Base64 a form of encryption?⌄
No. Base64 is encoding, not encryption. It provides no security — anyone can decode a Base64 string instantly. Never use it to protect sensitive data.
Can I encode images to Base64?⌄
Yes. Upload an image and the tool outputs the Base64 data URI that you can use directly in HTML or CSS.
Does the tool send my data to a server?⌄
No. All encoding and decoding happens in your browser using the JavaScript atob() and btoa() APIs.
What is the difference between Base64 and Base64URL?⌄
Base64URL replaces + with - and / with _ making it safe for use in URLs and JWT tokens. Switch between modes using the toggle in the tool.
Is there a file size limit?⌄
Files up to 5MB can be encoded. Larger files will process slowly due to browser memory constraints.
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