🏠 Home›Text›Base64 Encoder / Decoder
⚡ Quick Answer
Base64 is a way to encode binary data as plain ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). It is used to embed images in HTML/CSS, encode email attachments, store data in JSON, and work with APIs. 'Hello' in Base64 is 'SGVsbG8='. The = signs are padding characters.
🔤 Text

💻 Base64 Encoder / Decoder

Encode text to Base64 or decode Base64 back to readable text. Essential for web developers, API users, and anyone working with data encoding and email attachments.

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✨ Your Result
🦉Owl's Explanation
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Fill in the values above and click Calculate ✨

🤔 How Does This Work?

Base64 encoding works by converting binary data to ASCII text:

  • Each group of 3 bytes (24 bits) of input is split into four 6-bit groups
  • Each 6-bit group maps to one of 64 characters (A-Z, a-z, 0-9, +, /)
  • If input is not divisible by 3, = padding is added
  • Decoding reverses this — each Base64 character maps back to 6 bits, assembled into bytes

Our encoder uses JavaScript's btoa() for encoding and atob() for decoding, with UTF-8 support for non-ASCII characters.

✅ Trusted Tool
The 365tool.net Base64 Encoder/Decoder processes all text entirely in your browser. Your data is never sent to any server. Supports UTF-8 text including emoji and international characters. Free for developers and everyone. No sign-up needed.
❓ FAQ
What is Base64 used for?▼
Base64 is used to encode binary data as text so it can be safely transmitted through text-based systems. Common uses: embedding images in CSS/HTML (data URIs), encoding email attachments (MIME), storing binary data in JSON, and API authentication tokens (Basic Auth).
Why does Base64 end with = signs?▼
The = sign is padding. Base64 encodes 3 bytes of input into 4 characters of output. If the input length is not divisible by 3, padding = signs are added to make the output length divisible by 4. One = means 1 byte of padding, == means 2 bytes.
Is Base64 encryption?▼
No! Base64 is encoding, not encryption. It is easily reversible and provides no security. Anyone can decode Base64 instantly. Never use Base64 to hide sensitive data — use proper encryption instead.
How much larger is Base64 than the original?▼
Base64 increases data size by about 33%. This is because 3 bytes of binary data (24 bits) are represented as 4 Base64 characters (32 bits). A 100 KB image becomes about 133 KB when Base64 encoded.
What characters does Base64 use?▼
Standard Base64 uses: uppercase A-Z (26 chars), lowercase a-z (26 chars), digits 0-9 (10 chars), plus + and slash / (2 chars) = 64 characters total. URL-safe Base64 replaces + with - and / with _ to avoid URL encoding issues.
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