Base64 Encoder/Decoder

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data using only 64 printable ASCII characters: A–Z, a–z, 0–9, +, and /. It was designed to safely transmit binary data over channels that only support text, such as email (SMTP) or HTTP headers.

Base64 does not encrypt your data — it simply transforms it into a different representation. Anyone who sees a Base64-encoded string can decode it instantly. It exists to ensure safe transport, not secrecy.

Every 3 bytes of input become 4 characters of Base64 output, meaning Base64-encoded data is approximately 33% larger than the original.

How to Use This Tool

1. Paste your text or Base64 string into the input field.
2. Click Encode to convert plain text → Base64, or Decode to convert Base64 → plain text.
3. Click Copy Result to copy the output to your clipboard.

Common Use Cases

• HTTP Basic Authentication — Credentials are sent as Authorization: Basic base64(username:password)
• Data URLs — Embed images directly in HTML/CSS: src="data:image/png;base64,..."
• Email Attachments — MIME encoding converts binary attachments to Base64 for safe email transport
• JWT Tokens — JSON Web Tokens use Base64URL encoding for their header and payload sections
• API Payloads — Send binary data (images, files) inside JSON fields which only support text
• Config Files — Store binary certificates or keys as Base64 strings in YAML/JSON configs

Base64 vs Base64URL

Standard Base64 uses + and / which are special characters in URLs. Base64URL replaces + with - and / with _, making it safe for use in URLs, filenames, and JWT tokens without percent-encoding.