Base64 Decoder
This Base64 decoder turns encoded strings back into readable text or previews decoded images right in your browser. Paste a Base64 value and the result appears immediately; UTF-8 input is detected automatically, and URL-safe strings using - and _ are accepted too. Base64 appears everywhere in modern development, data URIs, JSON payloads, JWT segments, email attachments, and configuration files, so a quick local decoder is handy for debugging tokens and inspecting encoded assets. If the decoded bytes form an image, a preview is shown so you can verify it before saving. Decoding runs entirely client-side with JavaScript: nothing is uploaded, logged, or stored, and invalid input produces a clear error instead of silent garbage.
🖼️ Image Preview
How to use this tool
Overview
This Base64 decoder turns encoded strings back into readable text or previews decoded images right in your browser. Paste a Base64 value and the result appears immediately; UTF-8 input is detected automatically, and URL-safe strings using - and _ are accepted too. Base64 appears everywhere in modern development, data URIs, JSON payloads, JWT segments, email attachments, and configuration files, so a quick local decoder is handy for debugging tokens and inspecting encoded assets. If the decoded bytes form an image, a preview is shown so you can verify it before saving. Decoding runs entirely client-side with JavaScript: nothing is uploaded, logged, or stored, and invalid input produces a clear error instead of silent garbage.Formula
Base64 decode: binary-to-text → plain textFrequently asked questions
How do I decode Base64? +
Paste the Base64 string and press the decode button. The tool converts it to readable text, and if the bytes form an image you also get a preview.
Why does my decoded text look wrong? +
The string may be truncated, contain URL-safe characters, or use a different charset. Check that it is complete and try the URL-safe option or another charset.
Can I decode JWT parts? +
Yes. The header and payload of a JWT are Base64URL segments, so you can paste either part here to read the JSON without sending the token anywhere.
What is Base64 encoding? +
Base64 is a method of converting binary data into a text string using 64 ASCII characters. It is commonly used for embedding images in HTML, sending attachments via email, and storing binary data in text formats.
Can I encode and decode files, not just text? +
Yes. Upload any file, images, documents, or binary data, and the tool encodes it to Base64. You can also paste Base64 to decode it back to the original file.
Is there a character or file size limit? +
There is no artificial limit. Large files produce longer Base64 strings, but the tool handles them in the browser without issues.
What is the difference between Base64 encoding and encryption? +
Base64 encoding is NOT encryption. It is a reversible representation format. Anyone can decode Base64. It provides no security.