Base64 Encoder / Decoder
Encode and decode Base64 and URL-safe Base64 (base64url). UTF-8 aware, privacy-first, processed entirely in your browser.
Base64url replaces "+" with "-" and "/" with "_" and omits padding. Useful for URLs, JWTs, etc.
All processing is done locally in your browser. Your data never leaves your device.
What is Base64?
Base64 is a binary-to-text encoding that represents binary data using 64 ASCII characters. It is commonly used in data URLs, email (MIME), and to embed small assets.
- Base64url: URL-safe variant replacing + with - and / with _, usually without padding.
- UTF-8 aware: This tool handles Unicode properly when encoding/decoding.
- Local-only: Processing is 100% client-side for privacy.
How Base64 Encoding Works
Base64 turns every 3 bytes of binary into 4 text characters from a 64-character set. Padding with = aligns the output. The URL-safe form (Base64url) swaps + → - and / → _ and often omits padding.
Common Use Cases
- Embed small images/icons as Data URLs in HTML/CSS
- Transport binary safely in JSON or query strings
- Decode JWT segments (Base64url) to inspect claims
- Email MIME attachments and legacy transports
Step-by-Step: Encoding & Decoding
- Paste text or drop a file into the input box.
- Select Encode to convert text → Base64 or Decode to convert Base64 → text.
- Toggle URL-safe for Base64url when working with URLs/JWTs.
- Copy or download the result. No data ever leaves your browser.
Related Tools
- JWT Decoder – Decode Base64url segments and inspect claims.
- URL Encoder / Decoder – Safely encode URLs and query parameters.
- Case Converter – Quickly switch between common text cases.
Frequently Asked Questions
Is Base64 encryption?
No. Base64 is encoding, not encryption. It’s reversible and offers no security by itself.
When should I use Base64url?
Use Base64url for URL-safe contexts such as JWTs and query strings to avoid reserved characters.
Why does some Base64 end with = characters?
Padding aligns output to 4-character blocks. Base64url often omits padding while remaining decodable.
Does this tool send my data to a server?
No. All operations run locally in your browser for full privacy.