Base64 Decoder — Decode Base64 to Text, Images & Files
Decode Base64, Base64URL, or data URIs back to readable text or downloadable files. Free and private.
Quick answer
To decode Base64, paste the string into the KaviForge Base64 Decoder and the decoded text appears instantly. If the Base64 contains an image, PDF, or other binary file, the tool detects its type, shows a preview for images, and lets you download the decoded file. Base64URL and data URIs are handled automatically.
Base64 strings appear in API responses, JWTs, email sources, configuration files, and data URIs. This decoder turns them back into their original form — readable UTF-8 text or the original binary file.
It accepts standard Base64, URL-safe Base64URL, strings with missing padding, line breaks, and full data URIs, and gives a clear error when the input is not valid Base64.
How to Decode a Base64 String
- 1Paste your Base64 string, Base64URL string, or data URI into the input box.
- 2Read the decoded UTF-8 text in the output box — it updates as you type.
- 3If the data is an image, PDF, or other binary file, check the "Decoded file" section.
- 4Preview images directly and click "Download decoded file" to save the file.
- 5Copy or download the decoded text with one click.
Features
Base64 to Text
Decodes to UTF-8 so emoji and non-English characters display correctly.
Base64 to Image & File
Detects PNG, JPG, GIF, WebP, and PDF signatures and lets you download the file.
Base64URL & Data URIs
Handles - and _ characters, missing padding, and data:…;base64, prefixes.
Tolerant Input
Ignores whitespace and line breaks from email or PEM-style wrapped Base64.
Clear Error Messages
Explains exactly why an input is not valid Base64.
Private
Decoding happens in your browser — nothing is sent to a server.
When to Use the Base64 Decoder
Read Base64 in API responses
Decode Base64-encoded fields in JSON responses or webhooks to inspect their content.
Convert a Base64 string back to an image
Turn a data URI or Base64 image string from HTML, CSS, or a database into a PNG or JPG file.
Recover a PDF from Base64
Save Base64-encoded PDFs returned by document APIs as real PDF files.
Inspect email and MIME content
Decode Base64 email bodies and attachments copied from raw message source.
About the Base64 Decoder
The decoder normalizes the input (removing whitespace, converting Base64URL characters, and restoring padding), decodes it with atob, and then tries a strict UTF-8 decode.
If the bytes are not valid UTF-8 text, the tool treats the data as a binary file, detects the file type from its magic bytes, and offers it as a download instead of showing garbled characters.
Base64 Decoder FAQs
How do I decode Base64 to text?
Paste the Base64 string into the KaviForge Base64 Decoder. The decoded text appears immediately in the output box.
How do I convert a Base64 string to an image?
Paste the Base64 string or data URI. If it is an image, a preview appears in the "Decoded file" section and you can download it with the correct file extension.
Why do I get "Invalid Base64"?
The input contains characters outside the Base64 alphabet or has an impossible length. Check for copied quotes, spaces inside the string, or a truncated value.
Can it decode Base64URL from a JWT?
Yes. Base64URL characters (- and _) and missing padding are handled automatically. For full JWTs, use the JWT Decoder.
Does the decoder support UTF-8?
Yes. Decoded bytes are interpreted as UTF-8, so multilingual text and emoji display correctly.
Is my data uploaded?
No. All decoding runs locally in your browser.
Related Tools
Base64 Encoder
Encode text, files, and images to Base64 or data URIs. UTF-8 safe, with URL-safe Base64URL option.
JWT Decoder
Decode JSON Web Tokens to read the header, payload, and claims, and check if a token has expired.
URL Decoder
Decode percent-encoded URLs and query strings, and see every query parameter in a table.