Base64 Decoder
The Base64 Decoder converts Base64-encoded strings back to their original text or binary form. Base64 decoding is essential when working with encoded email attachments, data URIs, API tokens, JWT payloads, and embedded binary data. This decoder handles standard Base64, URL-safe Base64, and automatically detects padding. It also handles UTF-8 text properly, ensuring international characters and emojis are decoded correctly.
Formula
Base64 decoding: 1. Remove whitespace and padding 2. Map each character to 6-bit value 3. Combine into bytes (8-bit groups) 4. Convert bytes to text (UTF-8) Input: ASCII string Output: original binary or text
Example
Input: SGVsbG8gV29ybGQ= Output: Hello World Input: Q2FsY3p5 Output: Calczy
How to Use
- Paste your Base64 string into the input field
- Click decode to convert to text
- The output shows the decoded text
- If output is binary, download the file
- Copy the decoded text for your use
Frequently Asked Questions
What if the Base64 string is invalid?
The decoder checks the input for valid Base64 characters and correct padding. If invalid, it shows an error message. Common issues include missing padding (=), invalid characters, or incorrect length.
Can I decode URL-safe Base64?
Yes, the decoder handles both standard Base64 (with + and /) and URL-safe Base64 (with - and _). It automatically detects the variant and decodes accordingly.
Does the decoder handle binary data?
Yes, if the decoded output is binary (not text), the decoder shows a hex representation or offers a download. This is useful for decoding images, files, or other binary data embedded in Base64.
Is Base64 decoding the same as decryption?
No. Base64 is encoding, not encryption. Decoding Base64 does not require a key. Anyone can decode Base64. If you need secure data, use encryption (AES, RSA) instead.
Why does my decoded text show garbled characters?
This usually means the original text was not UTF-8 encoded, or the Base64 string was corrupted. Try different character encodings (UTF-16, Latin-1) or check the input for errors.