Mode:
Decoded text will appear here
Convert text to Base64 or decode Base64 back to text instantly with this free online tool. Features smart auto-detection that identifies whether your input is Base64 encoded or plain text. All processing happens in your browser — your data never leaves your device.
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It's commonly used to encode data that needs to be stored or transferred in environments that only support text, such as embedding images in HTML/CSS, encoding email attachments, storing complex data in JSON, and passing binary data through URLs. The name "Base64" comes from the 64 characters used in the encoding: A-Z, a-z, 0-9, +, and /.
Working with Base64 in your code? Here's how to encode and decode in popular languages:
Enter your text in the input panel. If auto-detect mode is enabled, the tool will recognize it as plain text and encode it automatically. You can also manually select "Encode" mode using the toggle or press 'E' on your keyboard.
Paste your Base64 string in the input panel. Auto-detect mode will recognize valid Base64 and decode it automatically. You can also manually select "Decode" mode using the toggle or press 'D' on your keyboard.
Base64 is used to encode binary data for text-only contexts: embedding images in HTML/CSS (data URIs), encoding email attachments (MIME), storing binary in JSON, encoding authentication credentials (HTTP Basic Auth), and passing data through URLs safely.
No. Base64 is encoding, not encryption. It transforms data into a different format but provides no security — anyone can decode Base64. Never use Base64 to "hide" sensitive data. For security, use proper encryption algorithms like AES.
Standard Base64 uses + and / characters, which have special meaning in URLs. Base64URL replaces these with - and _ to be URL-safe without additional encoding. JWTs and many web APIs use Base64URL. This tool uses standard Base64 encoding.
Base64 encoding increases size by approximately 33% because it represents 3 bytes of binary data as 4 ASCII characters. This overhead is the trade-off for text-safe representation. For large files, consider using direct binary transfer instead.
Yes. All encoding and decoding happens entirely in your browser using JavaScript. No data is ever sent to any server. Your last input and mode preference are saved in your browser's localStorage for convenience.
More DevDen tools: LLM Pricing Calculator · TOON Converter · JSON Formatter · URL Encoder/Decoder · Unix Timestamp Converter · Regex Tester · Hash Generator