Base64 Encoder / Decoder
Base64 FAQ
What is Base64 used for?
Base64 is used to encode binary data into a text format, making it safe to transmit over text-based protocols like email or JSON.
Is Base64 encryption?
No. Base64 is only an encoding scheme, not a form of encryption or hashing.
Why does Base64 increase data size?
Base64 encoding expands data size by about 33% since every 3 bytes of input become 4 bytes of output.
Can Base64 be reversed?
Yes. Base64 encoding is fully reversible, which means encoded data can always be decoded back to its original form.
Where is Base64 commonly used?
It is widely used in embedding images in HTML/CSS, encoding API keys, email attachments (MIME), and safely transmitting binary files in text protocols.
What is Base64 Encoding?
Base64 Encoding — Explained
Base64 is a binary-to-text encoding scheme that represents binary data in ASCII string format. It was originally designed to safely transmit binary data over channels that only support text, such as email, HTTP, or JSON.
Today, Base64 is used in a wide range of applications, including:
- Embedding images directly into
HTMLorCSSas data URIs. - Encoding API keys or authorization tokens in HTTP headers.
- Transferring binary files (e.g., PDFs, images) through text-based protocols like JSON or XML.
- Safely representing cryptographic data or certificates in readable form.
How Base64 Works
The algorithm groups input bytes into blocks of three (24 bits), then converts them into four 6-bit values. Each value is mapped to one of 64 characters in the Base64 alphabet.
| Step | Process | Example |
|---|---|---|
| 1. Grouping | Take 3 bytes (24 bits) | 01001000 01101001 00100001 |
| 2. Splitting | Divide into 4 groups of 6 bits | 010010 000110 100100 100001 |
| 3. Mapping | Convert each 6-bit group to Base64 alphabet | SGkh = "Hi!" |
Base64 Alphabet
Base64 uses 64 characters plus padding:
ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789+/
Padding is represented by =, used to ensure that the encoded output is a multiple of 4 characters.
Important Notes
- Data expansion: Base64 increases the size of data by about 33%.
- Not encryption: Base64 is purely an encoding scheme — it does not provide confidentiality or security.
- Compatibility: Avoids non-printable or special characters, making it safe for URLs, headers, and text files.
- Variants: Base64URL replaces
+and/with-and_for URL safety.
About This Tool
This Base64 Encoder/Decoder lets you instantly convert text or binary data to Base64 and back. All operations are performed client-side, meaning your input never leaves your browser.
Use this tool to encode images, text, or binary safely for transmission, storage, or API communication. Just remember: Base64 ≠ Security — if you need encryption, use a cryptographic algorithm instead.