Base64 Tool
Encode and decode Base64 instantly
Free online Base64 encoder and decoder. Convert text to Base64 and back instantly. Full UTF-8 support. Used for emails (MIME), data URIs, APIs, JWT tokens, HTTP auth, file uploads. NOT encryption—Base64 is reversible encoding for safe text-only transmission. Real-time conversion, 100% client-side, complete privacy.
What Is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of ASCII characters. It uses a set of 64 characters (A-Z, a-z, 0-9, +, /) to represent data, with = as padding. Base64-encoded output is approximately 33% larger than the original data, but it ensures safe transmission over text-only protocols.
Common Use Cases for Base64
- Email attachments (MIME): Binary files are Base64-encoded before embedding in email messages
- Data URIs: Embed images directly in HTML/CSS using
data:image/png;base64,... - API payloads: Encode binary data for transmission in JSON bodies
- JWT tokens: The header and payload of JWTs are Base64url-encoded
- Basic Authentication: HTTP Basic Auth encodes
username:passwordin Base64 - Configuration files: Kubernetes Secrets and AWS parameters store values as Base64
Base64 vs. Encryption
Base64 is not encryption. It is a reversible encoding — anyone can decode Base64 data without a key. Never use Base64 to protect sensitive information like passwords, API keys, or personal data. Use proper encryption (AES, RSA) or hashing (SHA-256) for security.