Free Online Base64 Encoder – Encode Text to Base64 Instantly
Type or paste any text, choose your options, and get the Base64 encoded result in one click.
What is Base64 Encoding?
Base64 encoding converts binary data or plain text into a string of 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It was designed to safely transmit data over channels that only handle text — such as email (MIME), JSON payloads, HTTP headers, and data URIs for images.
Every 3 bytes of input become 4 Base64 characters, which means encoded output is approximately 33% larger than the original. This is a deliberate trade-off for compatibility over text-only channels.
Encoding Examples
Quick Reference Examples
| Plain Text | Base64 Output | Try It |
|---|---|---|
| Hello World | SGVsbG8gV29ybGQ= | |
| ThinkForU | VGhpbmtGb3JV | |
| {"name":"John","age":30} | eyJuYW1lIjoiSm9obiIsImFnZSI6MzB9 | |
| Hello ๐ | SGVsbG8g8J+RjQ== | |
| https://www.thinkforu.org | aHR0cHM6Ly93d3cudGhpbmtmb3J1Lm9yZw== |
How to Use This Base64 Encoder
Type or paste any plain text into the input box, or click "Load Sample" to see an example.
Enable URL-safe mode, remove padding, or wrap output at 76 characters for MIME compatibility.
Click "Encode to Base64" or turn on Live Mode for instant real-time conversion as you type.
Copy the encoded string to clipboard or download it as a .txt file.
Click "Send to Decoder" to open the encoded result in the Base64 Decoder tool to verify it.
Click any "Try" button in the examples table to instantly load and encode a sample string.
Encoding Options Explained
Properly encodes multi-byte characters — emojis, accents, CJK characters. Always keep this enabled unless you specifically need ASCII-only encoding.
Replaces + with - and / with _. Use this when embedding Base64 in URLs, filenames, or JWT tokens to avoid percent-encoding issues.
Removes trailing = padding characters. Used together with URL-safe mode for JWT and other compact token formats.
Inserts line breaks every 76 characters. Required for MIME email encoding (RFC 2045) and PEM certificate format compatibility.
Who Uses Base64 Encoding?
Embed images as data URIs in HTML/CSS, encode API credentials for HTTP Basic Auth headers.
MIME encoding for email attachments and message bodies uses Base64 to safely transport binary data.
JWT header and payload are Base64url encoded. API keys and credentials are often transmitted as Base64.
Kubernetes secrets, Docker configs, and environment variables are commonly stored as Base64 strings.
Encode binary payloads, images, and configuration data for transmission through JSON APIs.
Understand how data encoding works in networking, security, and web development courses.
Frequently Asked Questions
Is my text sent to any server when encoding?
btoa() function and the TextEncoder API. Your data never leaves your device. See our Zero Data Storage Policy.Is Base64 encoding the same as encryption?
Why is the Base64 output 33% larger than the input?
What is URL-safe Base64 and when should I use it?
+ and / which have special meaning in URLs. URL-safe Base64 replaces these with - and _, making the output safe for URLs and filenames without extra percent-encoding. Use this when creating JWT tokens, URL parameters, or filenames.