Toolvantas

Developer utility

Base64 Encoder and Decoder

Encode plain UTF-8 text, URL-safe tokens, or local binary files into Base64 and Data URIs. Decode Base64 strings back into clean text or downloadable files with zero character corruption.

PNG, JPG, SVG, PDF, TXT supported (100% client-side)

Input Size0 B
Output Size0 B
Size Ratio100%

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme defined in RFC 4648 that maps binary bytes to 64 safe ASCII characters (A–Z, a–z, 0–9, +, and /, or - and _ in URL-safe mode).

  • Inline Data URIs: Embed small icons, SVGs, or fonts directly inside HTML and CSS (data:image/png;base64,...).
  • API & JWT Payloads: Safely carry binary keys, hashes, and URL-safe JWT claims inside JSON and HTTP headers.
  • Email Attachments: Powers MIME encoding for binary attachments over text-based mail protocols.

Full UTF-8 & binary file fidelity

Plain browser btoa() throws a range error on multibyte UTF-8 characters like accented letters, CJK scripts, and emojis.

This utility encodes and decodes text through native TextEncoder and TextDecoder byte buffers, and reads uploaded files as raw binary Uint8Array buffers so binary bytes and file sizes are never altered.

Frequently asked questions

What is Base64 encoding used for?

Base64 is used to transmit binary assets (such as images, certificates, or documents) across channels that only reliably accept plain ASCII text, such as JSON APIs, HTML Data URIs, and MIME email bodies.

Does Base64 provide encryption or security?

No. Base64 is an encoding format, not encryption. Anyone can decode a Base64 string instantly. Never use Base64 to conceal confidential passwords or API keys.

What is URL-safe Base64 (RFC 4648)?

URL-safe Base64 replaces + with - and / with _ and omits trailing = padding so encoded strings can be safely placed inside URLs and filenames.

Why does Base64 increase file size by roughly 33%?

Base64 uses 4 characters (6 bits each) to represent every 3 bytes (24 bits) of source binary data. This 4:3 ratio results in an approximate 33% increase in payload size.

Does this tool support emojis and non-English UTF-8 characters?

Yes. Our encoder and decoder uses a full UTF-8 byte stream pipeline, preserving emojis, mathematical notation, and international scripts cleanly.

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