Base64 Encoder

How to use the Base64 Encoder tool

1. Type or paste text into the left editor. The Base64 output appears on the right as you type.
2. To encode a file, click Upload File and pick a text file; its contents are loaded into the editor.
3. Click Load URL to fetch text from an endpoint that allows cross-origin requests.
4. Click Copy Result to copy the encoded string. The status bar under each panel shows the size, so you can see the 33% growth.
5. Dummy Data loads a sample with accented characters and emoji, which shows why btoa() alone is not enough. Clear resets both panels.

How to Base64 encode a string in JavaScript, PHP and Python

const text = "Hello, wörld! 🌍";

// Node.js: Buffer handles any Unicode string
const encoded = Buffer.from(text, "utf8").toString("base64");
console.log(encoded); // SGVsbG8sIHfDtnJsZCEg8J+MjQ==

// Browser: btoa() only accepts Latin-1, so UTF-8 encode first
const bytes = new TextEncoder().encode(text);
const browserEncoded = btoa(String.fromCharCode(...bytes));
console.log(browserEncoded === encoded); // true

// URL-safe variant (RFC 4648 section 5), no padding
console.log(Buffer.from(text).toString("base64url"));

<?php
$text = "Hello, wörld! 🌍";

$encoded = base64_encode($text);
echo $encoded, PHP_EOL; // SGVsbG8sIHfDtnJsZCEg8J+MjQ==

// URL-safe variant: swap + and /, strip = padding
$urlSafe = rtrim(strtr($encoded, '+/', '-_'), '=');
echo $urlSafe, PHP_EOL;

// Encode a file, for example an image
// $encoded = base64_encode(file_get_contents('logo.png'));

import base64

text = "Hello, wörld! 🌍"

# b64encode works on bytes, so encode the string as UTF-8 first
encoded = base64.b64encode(text.encode("utf-8")).decode("ascii")
print(encoded)  # SGVsbG8sIHfDtnJsZCEg8J+MjQ==

# URL-safe variant uses - and _ instead of + and /
print(base64.urlsafe_b64encode(text.encode("utf-8")).decode("ascii"))

# From the shell:  echo -n "hello" | base64

Common errors and how to fix them

InvalidCharacterError: The string to be encoded contains characters outside of the Latin1 range

btoa() only accepts code points 0 to 255. Convert the string to UTF-8 bytes with TextEncoder first, as in the JavaScript snippet above.

Encoded output ends in Cg== or CG== and does not match another tool

Your input has a trailing newline, usually from echo or a file saved by an editor. Use echo -n or printf, or strip the newline before encoding.

Base64 breaks a URL or query string

Standard Base64 uses + / and =, which have meaning in URLs. Use the base64url variant, or percent-encode the value.

The receiving side rejects the string because of line breaks

Some encoders (MIME, openssl base64) wrap output at 64 or 76 characters. Remove the newlines, or pass -A to openssl to get a single line.

Good to know