Base64 Decoder
Decode encoded string data or binary files into human-readable plain text, images, or downloadable files with multi-charset support.
⚙️ Advanced Options
📁 Decode Binary Files & Documents
Select an encoded text file or binary file containing encoded data to process and download.
Click (or tap) here to select a file
Supports text files, images, PDFs, or raw binary payloads
📜 Recent Decoded History
No recent decodes saved yet. Decode any encoded payload above to save your history locally.
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Base64 Decoder & Encoder Overview
Welcome to Base64 Decoder Online, the ultimate 100% client-side Base64 decoder and Base64 encoder utility. Effortlessly decode Base64 strings, convert Base64 payloads back to plain text, or decode binary files directly in your web browser.
Base64 encoding and decoding schemes are widely used across modern software engineering when transferring binary data over text-based protocols like MIME email, HTTP headers, XML, and JSON payloads. Using an online Base64 decoder ensures that raw binary files, images, or formatted data remain intact without corruption during network transmission.
Advanced Base64 Decoding Options
Our free Base64 decode tool includes professional configuration settings to handle complex payloads:
- Multi-Charset Base64 Decoding: Specify character sets (UTF-8, ASCII, ISO-8859-1, Windows-1252, Shift-JIS, etc.) to ensure decoded text characters display perfectly.
- Line-by-Line Base64 Decode: Automatically strip non-encoded whitespaces and decode multi-line entries separately.
- Instant Live Mode Decoding: Perform real-time Base64 decoding as you type using high-performance browser JavaScript APIs.
Safe & Secure Base64 Decode Process
Security and privacy are paramount when processing sensitive tokens or developer payloads. Our online Base64 decoder operates 100% locally inside your browser's client-side memory. Your data is never uploaded to any remote server or stored in any database.
Base64 Encoding & Decoding Mechanics
The Base64 decode algorithm parses ASCII characters and maps them back into standard 8-bit binary byte arrays. Each Base64 character represents exactly 6 bits of binary data.
Example: ASCII Byte Sequence Encoding
Here's a quote snippet from Thomas Hobbes's Leviathan:
"Man is distinguished, not only by his reason, but ..."
This is represented as an ASCII byte sequence and encoded in MIME's standard scheme as follows:
TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCAuLi4=| Text content | M | a | n |
|---|---|---|---|
| ASCII Code | 77 | 97 | 110 |
| Bit Pattern | 01001101 | 01100001 | 01101110 |
| Encoding Index | 19 (T) | 22 (W) | 5 (F), 46 (u) |
| Encoded Character | T | W | F u |
Base64 Decode Code Examples across Programming Languages
base64_decode($str)base64.b64decode(s)atob(str)Base64.getDecoder().decode()Convert.FromBase64String()base64.StdEncoding.DecodeString()Base64.decode64(str)decode_base64($str)base64 --decodeFROM_BASE64(str)decode(str, 'base64')base64::decode(str)