Easy Converter

Base64 Encoder / Decoder

Encode any text or file to Base64, or decode a Base64 string back to its original form. Useful for embedding images in CSS, signing JWTs by hand, building data URIs, or transmitting binary data through plain-text channels (email, JSON, form fields). UTF-8 safe and works fully offline.

How to use

  1. 1

    Paste text or upload a file

    Drop text into the editor or pick a file to encode. Files up to 100 MB are supported.

  2. 2

    Pick direction and variant

    Encode or decode; standard or URL-safe Base64.

  3. 3

    Copy or download

    Click Copy for text or Download for binary output.

Technical details

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string using a 64-character alphabet (A–Z, a–z, 0–9, + and /). Each three input bytes produce four output characters, which makes Base64 ~33% larger than the original. It is the standard way to embed binary content in formats that only allow text.

For text input, the tool encodes the UTF-8 bytes of the string. For files, it reads the binary content with the FileReader API and outputs the raw Base64 representation. URL-safe Base64 (replacing `+/` with `-_` and dropping padding) is available for JWT, OAuth and JWS use cases.

Decoding accepts both standard and URL-safe Base64 and auto-detects padding. If the input is not valid Base64, the tool highlights the offending character instead of silently producing garbage.

Base64 should never be considered encryption: it is a perfectly reversible encoding that anyone can decode without a key. To protect data, encrypt with AES-GCM and Base64 the ciphertext.

Frequently asked questions

Is Base64 encryption?
No. It is reversible without a key. Use real encryption (AES-GCM) for confidentiality.
Why is the result 33% larger?
Base64 uses 4 characters per 3 bytes of input. This overhead is the price of being ASCII-safe.
Can I encode files?
Yes. Drop any file up to ~100 MB. The output is a Base64 string ready to paste into CSS, JSON or email.
What is URL-safe Base64?
A variant that replaces + and / with - and _ so the string can travel inside URLs without further encoding. Used in JWT and OAuth.
Are my files uploaded?
No. Encoding is performed locally in your browser via FileReader and TextEncoder.
Reviewed by:Easy Converter Engineering Team

This tool was tested and calibrated by our engineering team. All processing happens locally in your browser — your files and data never leave your device.