Base64 Encoder/Decoder Tool - Online & Free
Encode and decode Base64 online in real time, converting text and files instantly. Secure client-side processing, no upload, free, and fast.
Online Base64 Encoder and Decoder
Welcome to the ultimate Online Base64 Encoder and Decoder. This simple yet powerful tool allows you to convert text to Base64 or decode Base64 strings back to human-readable text instantly.
Base64 encoding schemes are essential when encoding binary data for storage or transfer over media designed for text (like HTTP or SMTP).
Advanced Configuration Options
Character Set Selection
When dealing with textual data, specifying the correct character set (charset) is crucial. While UTF-8 is the standard, legacy systems may use ASCII, ISO-8859-1, or others.
Decode Each Line Separately
Encoded data often appears as a continuous block of text. However, if you have multiple independent Base64 strings separated by newlines, enable this option.
Live Conversion Mode
Enable Live Mode for instant results as you type. This mode performs Base64 conversion locally in your browser using JavaScript, ensuring zero latency.
Secure and Private
Your privacy is our priority. All communications use secure SSL encrypted connections (HTTPS). We never inspect, store, or share your submitted data.
Completely Free Online Tool
Our Base64 tool is 100% free to use. No software installation, registrations, or subscriptions required.
Design Principles
A Base64 index table consists of 64 characters chosen to be both common to most encodings and printable. This minimizes the risk of data modification by systems like email servers.
What is Base64 Encoding?
Base64 is a group of binary-to-text encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation.
Base64 Encoding Example
Consider this quote from Thomas Hobbes's Leviathan:
"Man is distinguished, not only by his reason, but ..."
When encoded into MIME Base64, this ASCII sequence becomes:
TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5IGhpcyByZWFzb24sIGJ1dCAuLi4=How it works: The word "Man" is encoded as "TWFu". In ASCII, "M", "a", "n" are bytes 77, 97, 110. Their binary representations are joined and divided into 6-bit groups.
| Text content | M | a | n | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ASCII Value | 77 | 97 | 110 | |||||||||||||||||||||
| Binary | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0 |
| Index | 19 | 22 | 5 | 46 | ||||||||||||||||||||
| Base64 | T | W | F | u | ||||||||||||||||||||
As shown, Base64 encoding converts 3 bytes of input data (24 bits) into 4 Base64 characters (6 bits each), expanding the data size by approximately 33%.
Paste text or drop a file and this tool instantly converts it to a Base64 string, or decodes any Base64 input back to readable text or a downloadable file. Encoding and decoding both run client-side in your browser, support UTF-8 and legacy charsets, and offer a live mode that updates results as you type. Nothing is uploaded to a server.
How to Use the Base64 Encoder and Decoder
- 1
Choose encode or decode
Select Encode to turn text or a file into Base64, or Decode to convert a Base64 string back to its original form.
- 2
Enter your input
Type or paste your content into the input box, or drag and drop a file (up to 10MB) to load it directly.
- 3
Set options if needed
Pick a character set for text data, or enable Decode each line separately when handling multiple Base64 strings split by newlines.
- 4
Get the result instantly
With Live Mode on, the output updates as you type; otherwise click Encode or Decode to process.
- 5
Copy or download
Use Copy to send the result to your clipboard, or Download to save the decoded file or encoded text locally.
References
- RFC 4648 — Base16, Base32, and Base64 Data Encodings
The authoritative IETF specification defining the Base64 alphabet, padding, and encoding rules.
- MDN — Base64 (Glossary)
A concise overview of what Base64 is and when binary-to-text encoding is used on the web.
- MDN — btoa()
The Web API method used to Base64-encode a string in JavaScript, with notes on Unicode handling.
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Frequently Asked Questions
- What is Base64 encoding?
- Base64 is a group of binary-to-text encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation.
- Why are these specific 64 characters used?
- A Base64 index table consists of 64 characters chosen to be both common to most encodings and printable. This minimizes the risk of data modification by systems like email servers.
- Does Base64 encoding make my data larger?
- Yes. Base64 converts every 3 bytes of input (24 bits) into 4 Base64 characters (6 bits each), expanding the data size by approximately 33%.
- Is Base64 encoding the same as encryption?
- No. Base64 is an encoding, not encryption. Anyone can decode a Base64 string back to its original form, so it provides no confidentiality—it only makes binary data safe to transport over text-based channels.
- Is my data sent to a server?
- No. All encoding and decoding run entirely in your browser using built-in JavaScript APIs. Your text and files never leave your device.
- Can I encode and decode files, not just text?
- Yes. Drag and drop or upload a file up to 10MB to encode it to Base64, and use the Download button to save a decoded file back to disk.