Question 1

What is Base64?

Accepted Answer

Base64 is a way to represent any bytes as text using 64 safe characters: A–Z, a–z, 0–9, + and /. Every 3 bytes become 4 characters, so the output is about 33 % larger than the input. It exists so binary data (images, files, encrypted blobs) can travel through systems built for text — email, JSON, HTML, URLs.

Question 2

Why does my decoded Base64 look like garbage?

Accepted Answer

Because the Base64 probably encodes a binary file, not text. A string starting with iVBORw0KGgo is a PNG image, /9j/ is a JPEG, JVBERi0 is a PDF. This tool decodes to UTF-8 text; to view a file, put the string in a data URI (data:image/png;base64,…) and open it in a browser.

Question 3

What does the = at the end mean?

Accepted Answer

Padding. Base64 works in groups of 3 input bytes; if the input length is not a multiple of 3, one or two = signs pad the final group. URL-safe Base64 (RFC 4648 §5) usually drops the padding and swaps + and / for - and _ so the string can sit in a URL or filename without escaping.

Question 4

Is Base64 encryption?

Accepted Answer

No. Anyone can decode it instantly — it hides nothing. It is an encoding for transport, not a security measure. Passwords or tokens in Base64 (for example in HTTP Basic auth headers) are effectively plain text unless the connection itself is encrypted with HTTPS.

Question 5

Is my text or file uploaded?

Accepted Answer

No. Encoding and decoding run entirely in your browser with the built-in btoa/atob functions and the FileReader API. Nothing is sent to a server, which also makes it safe for API keys and private data.

Base64 Encode & Decode

How Base64 works

Frequently asked questions

Related tools