Base64 Decoder
Decode Base64 encoded string data or files into human-readable text or downloadable files.
⚙️ Advanced Options
📁 Decode Files from Base64 Format
Select an encoded text file or binary file containing Base64 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 Base64 payload above to save your history locally.
Base64 Decoder & Encoder Overview
Welcome to Base64 Decoder Online, a simple and powerful tool to decode Base64 strings and encode data into Base64 format effortlessly. Convert Base64 encoded text, binary data, images, or documents back to human-readable format with 100% browser-based privacy.
Base64 decoding is an essential operation when dealing with binary data transmitted across text-oriented media. By translating binary bytes into 64 safe ASCII characters, Base64 ensures data integrity across email protocols (MIME), HTTP parameters, JSON Web Tokens (JWT), XML schemas, and web APIs.
Advanced Base64 Decoding Options
Our free online Base64 decoder includes advanced conversion features:
- Character Set Selection: Specify custom text encodings (UTF-8, ASCII, ISO-8859-1, Windows-1252, etc.) for accurate character decoding.
- Decode Each Line Separately: Useful for batch processing multiple Base64 encoded strings separated by newlines.
- Live Instant Decoding: Real-time decoding using browser JavaScript execution without remote server calls.
Safe and Secure Base64 Decode Process
All Base64 decode operations are executed locally within your browser memory. We never store, inspect, or upload your input strings or binary files to any external server.
Details of Base64 Encoding & Decoding
The Base64 decode process reads 4 encoded ASCII characters (24 bits) and reconstructs the original 3 binary bytes (24 bits).
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 Base64 scheme as follows:
TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCAuLi4=| Text content | M | a | n |
|---|---|---|---|
| ASCII Code | 77 | 97 | 110 |
| Bit Pattern | 01001101 | 01100001 | 01101110 |
| Base64 Index | 19 (T) | 22 (W) | 5 (F), 46 (u) |
| Base64 Encoded | 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)Frequently Asked Questions
What is Base64 decoding?
Base64 decoding converts a Base64 encoded string back to its original binary or text data. Base64 encodes binary data as ASCII characters, making it safe for transmission over text-based protocols.
Is this Base64 decoder free?
Yes, completely free with no limits, no sign-up, and no data uploads. All decoding happens locally in your browser.
What is URL-safe Base64?
URL-safe Base64 replaces + with - and / with _ so the output can be used in URLs and file names without percent-encoding.
