Free Base64 Encoder Decoder
Encode text to Base64 or decode Base64 to text instantly. 100% client-side, no uploads, no signup, no tracking — works entirely in your browser.
Your data never leaves your browser. All encoding and decoding happens locally using JavaScript. No tracking, no signup, no uploads.
Base64 Encoder & Decoder — Fast, Secure, and 100% Free
Our free Base64 encoder decoder helps you convert text to Base64 and decode Base64 strings back to readable text instantly. Whether you're working with API tokens, inspecting JWT headers, debugging HTTP Basic Authentication, or generating data URIs, this online Base64 tool handles it all — directly in your browser with zero server uploads.
Switch between encoding (text to Base64) and decoding (Base64 to text) with a single click.
Easily copy results to clipboard, paste from clipboard, or download as a .txt file.
Works offline and in real-time — just click "Convert" and see results immediately.
Properly handles emojis, international characters, and non-ASCII text — no more "InvalidCharacterError".
Your data stays on your device. No uploads, no servers, no tracking. Complete privacy.
Use the Base64 encoder decoder immediately — no registration, no email, no payment.
How to Use This Free Base64 Encoder Decoder
1. Enter your text or Base64 string into the input box on the left.
2. Select mode: "Encode (Text → Base64)" or "Decode (Base64 → Text)".
3. Click "Convert" or use the Swap button to quickly switch between modes.
4. Copy the result to your clipboard, download as a .txt file, or use it directly in your project.
5. Use the Sample button to test the tool with example text.
Why Use a Base64 Encoder/Decoder?
- API Development — Encode API keys, authentication tokens, and binary data for JSON payloads.
- JWT Debugging — Decode JWT header and payload segments without external tools.
- Data URIs — Generate Base64 data URIs for images, fonts, and other assets.
- Email MIME — Encode attachments and email bodies for SMTP transmission.
- Cross‑platform Testing — Verify Base64 strings across different systems quickly.
What is Base64? How Does Base64 Encoding Work?
Base64 is a binary-to-text encoding scheme that represents binary data using a 64-character ASCII alphabet (A–Z, a–z, 0–9, +, /). It converts every 3 bytes (24 bits) into 4 characters of Base64. When the input is not a multiple of 3 bytes, the encoder adds padding with "=" characters. Base64 is widely used in email attachments (MIME), JSON web tokens (JWT), HTTP Basic Authentication, and data URIs in HTML/CSS. Remember: Base64 encoding is not encryption — it's just a way to safely transmit binary data over text-only protocols.
Complete Base64 Reference Guide
Our online Base64 encode decode tool supports the standard Base64 alphabet as defined by RFC 4648. It also includes proper UTF-8 handling, so emojis and special characters are encoded and decoded correctly. Common use cases include encoding JWT tokens, embedding images as Base64 in CSS, storing binary data in databases, and building cross-platform APIs. No matter your use case, this free Base64 encoder runs entirely in your browser with zero latency and complete privacy.
Frequently Asked Questions
Learn how to use this tool correctly by reading our step-by-step tutorial.
