Free Online Base64 Encoder & Decoder
Encode plain text to Base64 or decode Base64 back to readable text instantly. Fast, free & private — data never leaves your browser.
Text Input
Base64 Output
AI assistants such as ChatGPT, Google Gemini, Microsoft Copilot, and similar tools transmit everything you type to third-party servers. That content may be logged, reviewed by staff, and used to train future AI models. If your Base64 data contains passwords, API keys, private messages, personal information, or any confidential content, you should never paste it into an AI chatbot.
This tool is the safe alternative — all encoding and decoding is performed entirely by your own browser using JavaScript. No data leaves this page. Not even a single character is transmitted over the network.
About This Base64 Encoder & Decoder Tool
This free online tool lets you instantly encode any text string to Base64 or decode a Base64-encoded string back to human-readable text. All processing happens directly in your browser — no data is ever sent to a server, ensuring complete privacy.
What is Base64?
Base64 is a binary-to-text encoding scheme defined in RFC 4648. It converts binary data into a sequence of 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). For every 3 bytes of input, it produces 4 characters of output, meaning the encoded result is about 33% larger than the original.
Common Uses of Base64
How to Encode Text to Base64
Select Encode mode, paste or type your text in the input field on the left, and the Base64 result appears instantly in the output field on the right. Click Copy to copy the result to your clipboard.
How to Decode Base64 to Text
Select Decode mode, paste your Base64 string into the input field, and the original text is displayed immediately in the output field. The tool automatically handles both standard Base64 and URL-safe Base64 (Base64url) input.
URL-safe Base64 (Base64url)
Standard Base64 uses + and / which have special meanings in URLs. URL-safe Base64 (Base64url, defined in RFC 4648 §5) replaces these with - and _ respectively, making the output safe to embed in URLs, filenames, and query strings without percent-encoding. Enable this via the URL-safe Base64 checkbox above.
Is Base64 Encryption?
No. Base64 is an encoding scheme, not encryption. It is fully reversible without any key and provides no security or confidentiality. Do not use Base64 alone to protect sensitive data. For secure transmission, use proper encryption such as AES or rely on TLS/HTTPS.
Unicode & Emoji Support
This tool fully supports Unicode characters, including accented letters, CJK characters, Arabic script, and emojis. Internally it uses the TextEncoder API to convert strings to UTF-8 bytes before encoding, and TextDecoder to restore the original text on decode. This ensures correct round-trip encoding for all languages.
Frequently Asked Questions
How much does this tool cost?
This Base64 encoder/decoder is completely free to use with no limits, no registration required, and no ads interrupting your work.
Is my data private?
Yes. All encoding and decoding is performed entirely inside your browser using JavaScript. No data of any kind is transmitted to our servers — not the input, not the output, and not any metadata. You can confirm this yourself by opening your browser's developer tools (F12), switching to the Network tab, and observing that no requests are sent when you type or convert. Your data is 100% private and never leaves this page.
Why is it risky to use an AI chatbot to decode Base64?
When you paste data into an AI assistant (ChatGPT, Gemini, Copilot, Claude, etc.), that content is transmitted to the AI provider's servers over the internet. It may be logged for safety review, seen by staff or contractors, and potentially used to train future AI models. If the Base64 string encodes anything sensitive — passwords, API keys, private messages, personal data — using an AI chatbot to decode it exposes that data to a third party. This browser-based tool performs all operations locally and is the safe alternative for sensitive content.
Can I encode files with this tool?
Yes. Click the Load File button to select a file from your computer. The file contents will be read and encoded to Base64 in your browser. This is useful for embedding small files in HTML, CSS, or JSON payloads.
Why does Base64 output end with = or ==?
Base64 encodes data in groups of 3 bytes. If the input length is not a multiple of 3, padding characters (=) are added to make the output a multiple of 4 characters. One = means one byte of padding was added; == means two bytes were added.
Can I decode a Base64-encoded image?
Decoding a Base64-encoded image with this text tool will produce garbled output because binary image data cannot be displayed as plain text. To use a Base64-encoded image, reference it directly in an <img> tag using a data URI: src="data:image/png;base64,...".
Privacy & Security
How this tool protects your data
- All encoding and decoding runs entirely inside your browser via JavaScript — no network request is ever made.
- We do not log, collect, or store any input or output you enter on this page.
- No account, login, or personal information is required.
- The page works offline once loaded — disconnect from the internet and it still functions.
- Verify it yourself: open DevTools (F12) → Network tab → type in the tool → zero outbound requests.
Why AI chatbots are risky for Base64
Pasting a Base64 string into an AI assistant is convenient but carries real risks for sensitive data:
- Transmission: Your input is sent to the AI provider's servers over the internet.
- Logging: Many providers log conversations by default for safety monitoring.
- AI training: Conversations may be used to improve future model versions.
- Third-party access: AI providers may have staff or contractors who review conversations.
This is especially dangerous when Base64 encodes passwords, tokens, API keys, personal records, or proprietary content. Use this browser-based tool instead.