What is Base64 decoding?

Base64 decoding is the reverse of encoding — it converts a Base64 ASCII string back into the original binary data or text.

What does 'Invalid Base64' mean?

This error means the input is not valid Base64. Common causes include missing padding characters (=), invalid characters, or whitespace. Try trimming whitespace from your input.

Is decoded data safe to use?

Base64 decoding just converts data format. Always be cautious with decoded content from untrusted sources, especially if it contains HTML or executable code.

Can I decode Base64 images?

This tool decodes Base64 to text. For Base64-encoded images (data URLs), the decoded output will show binary data. Use a dedicated image decoder for visual output.

Base64 Decode Online

Decode Base64 encoded strings back to readable text instantly. Free, fast, and runs entirely in your browser — no data ever leaves your device.

Base64 Input

What is Base64 Decode?

Base64 decoding is the process of converting a Base64-encoded string back to its original text or binary data. Base64 is a text-safe encoding format commonly used to transmit binary data over protocols that only handle ASCII text, such as email, HTTP headers, and JSON payloads. When you receive a Base64 string, you need to decode it to read the original content.

Common scenarios where you need to decode Base64 include: inspecting JWT token payloads (the middle section of a JWT is Base64url-encoded), reading data URI image payloads, decoding email attachments, examining HTTP Basic Authentication credentials, and parsing API responses that encode binary fields as Base64.

This decoder handles all standard Base64 as well as Base64url (used in JWTs, which replaces + with - and / with _). It fully supports Unicode, CJK characters, emojis, and any other UTF-8 encoded text. All decoding happens entirely in your browser.

How to Use

1
Paste your Base64 string
Copy and paste the Base64 encoded string into the input field.
2
Click Decode
Press "Decode from Base64" to convert the encoded string back to readable text.
3
Copy the result
Use the Copy button to copy the decoded text to your clipboard.

Features

Decode any Base64 string to plain text
Supports Unicode-encoded Base64 strings
Instant decoding with clear error feedback
Works entirely in your browser
No data sent to any server
Free with no limits or sign-up

Frequently Asked Questions

QWhat is Base64 decoding?: Base64 decoding is the reverse of encoding — it converts a Base64 ASCII string back into the original binary data or text.
QWhat does 'Invalid Base64' mean?: This error means the input is not valid Base64. Common causes include missing padding characters (=), invalid characters, or whitespace. Try trimming whitespace from your input.
QIs decoded data safe to use?: Base64 decoding just converts data format. Always be cautious with decoded content from untrusted sources, especially if it contains HTML or executable code.
QCan I decode Base64 images?: This tool decodes Base64 to text. For Base64-encoded images (data URLs), the decoded output will show binary data. Use a dedicated image decoder for visual output.