Encode and decode Base64

1. Choose Encode or Decode.
2. Paste your text or click Encode a file.
3. When encoding, select URL-safe Base64 if you’re using the result in a link, JWT, or filename.
4. Copy the result, or click Download decoded file if the decoded content is a file.

How Base64 works

Base64 represents binary data using just 64 text-safe characters (A–Z, a–z, 0–9, +, and /). Every 3 bytes become 4 characters, so the result is about 33% larger than the original. If the total number of bytes isn’t divisible by 3, the result ends with = or == padding.

Where Base64 is used

• Embedded images in HTML/CSS, such as data:image/png;base64,… — when you encode a file here, the result already uses this format. For images, you can also use our image to Base64 tool.
• Email attachments (MIME) and PEM-format certificates.
• APIs that accept PDFs or photos inside JSON.
• JWT tokens, which use the URL-safe variant without padding — to read one, use our JWT decoder.

The URL-safe variant (RFC 4648, Section 5) replaces + with - and / with _, characters that don’t need to be encoded in links.

Base64 doesn’t protect your data

Anyone can decode Base64 in seconds, with no key. Don’t use it to “hide” passwords or personal information—you need real encryption for that. If the decoded content isn’t text (for example, an image, PDF, or ZIP file), the tool will let you know it’s binary and offer a download. When you download it, rename the file with the correct extension (.pdf, .png…).