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Base64 Encoder / Decoder

Encode text and files to Base64, or decode Base64 strings instantly. 100% client-side.

Encode

Drag & drop a file here, or click to select

Base64

All processing is done entirely in your browser. No data is sent to any server.

What is Base64?

Base64 is an encoding scheme that converts binary data into ASCII text using 64 safe characters (A–Z, a–z, 0–9, +, /). It is widely used in email attachments (MIME), HTTP headers, JWT tokens, and inline image embedding. Note that Base64 is encoding, not encryption — anyone can decode it. Never store sensitive data in Base64 without additional encryption.

Use Cases for Base64 Encoding

Email Attachments (MIME)

Binary attachments such as images and documents are converted to Base64 to safely transmit them as ASCII text in email.

HTTP Basic Authentication

Credentials in the format username:password are Base64-encoded and sent in the Authorization header.

JWT (JSON Web Token)

JWT header and payload are encoded with URL-safe Base64 (Base64URL). This tool works great alongside the JWT Decoder.

Inline Image Embedding

Images are embedded directly in HTML or CSS as data URIs using Base64, eliminating the need for separate image requests.

Standard vs URL-safe Base64

ItemStandardURL-safe
Special chars+, /-, _
Padding=Omitted
Common useEmail, general encodingURL, JWT, filenames

Frequently Asked Questions

Is Base64 the same as encryption?
No. Base64 is just an encoding scheme, not encryption. Anyone can decode a Base64 string without any key. If you need security, apply actual encryption (such as AES) separately.
Does Base64 increase file size?
Yes, by approximately 33%. Base64 represents every 3 bytes as 4 ASCII characters, which increases the data size.
Can I encode Korean (non-ASCII) text with Base64?
Yes. Korean and other non-ASCII characters are first converted to UTF-8, then encoded with Base64. This tool handles that automatically.
What is URL-safe Base64?
URL-safe Base64 replaces the standard + and / characters with - and _ to avoid issues in URLs and filenames. It is used in JWT tokens, OAuth, and similar contexts.
What is the = padding at the end of Base64?
Base64 processes input in 3-byte blocks. The = padding characters align the output to a multiple of 4 characters. There can be 0, 1, or 2 padding characters depending on the input length.
Can I convert an image to Base64?
Yes. Upload any image file and this tool will convert it to a Base64 data URI (data:image/...;base64,...) that you can embed directly in HTML or CSS.
Is the data I enter sent to a server?
No. All encoding and decoding is performed entirely in your browser using JavaScript. Nothing is transmitted to any server.

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