Question 1

What is Base64 encoding?

Accepted Answer

Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). It's commonly used to embed binary data like images or files inside text-based formats such as HTML, CSS, JSON, or email (MIME). The encoded output is roughly 33% larger than the original data.

Question 2

When should I use Base64 encoding?

Accepted Answer

Common use cases include: embedding small images directly in HTML/CSS (data URIs), sending binary data in JSON APIs, encoding email attachments (MIME), storing binary data in text-only databases or config files, and passing data in URL parameters (using URL-safe Base64). It's not meant for encryption or compression — it's purely for safe text transport of binary data.

Question 3

Is Base64 encoding the same as encryption?

Accepted Answer

No. Base64 is not encryption and provides zero security. It's a simple encoding that anyone can decode instantly. Never use Base64 to hide passwords, API keys, or sensitive data — it's trivially reversible. For security, use proper encryption algorithms like AES or secure hashing like bcrypt.

Question 4

Why does Base64 make data larger?

Accepted Answer

Base64 converts every 3 bytes of input into 4 ASCII characters, resulting in roughly a 33% size increase. This is because each Base64 character encodes 6 bits of data (2^6 = 64 possible characters), but takes up 8 bits in ASCII. So 3 bytes (24 bits) become 4 characters (32 bits). Padding characters (=) are added when the input length isn't divisible by 3.

Question 5

What characters are used in Base64?

Accepted Answer

Standard Base64 uses 64 characters: uppercase A-Z (26), lowercase a-z (26), digits 0-9 (10), plus (+), and forward slash (/). The equals sign (=) is used for padding. URL-safe Base64 variants replace + with - and / with _ to avoid issues in URLs and filenames.

Question 6

Can I encode non-ASCII or Unicode text in Base64?

Accepted Answer

Yes, but you need to handle the encoding properly. This tool uses UTF-8 encoding for Unicode text before Base64 encoding, so accented characters, CJK characters, and emoji will all encode and decode correctly. Some simpler tools only handle ASCII, which can cause data loss with international text.

Base64 Encoder / Decoder

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