Base64 Encoder + Decoder
Base64 turns any bytes into ASCII-safe text — useful for embedding images in HTML/CSS, sending binary data through text-only protocols, or decoding things like JWT payloads. MiniMax Converter handles both directions: paste text or drop a file to encode, paste Base64 to decode. Supports standard Base64 and base64url (the URL-safe variant used in JWTs).
When you need it
Data URIs: data:image/png;base64,iVBORw0K... embedded directly in HTML/CSS. JWT payloads: the second segment of a JWT is base64url-encoded JSON. Email attachments: binary files transmitted as Base64 in MIME bodies. API keys / tokens: sometimes printed as Base64 strings. Quick binary-in-text-config: embedding a small binary blob in a JSON / YAML file.
How to use it
- Open Tools → Convert & Format → Base64.
- To encode: paste text or drop a file. Output in the bottom panel — Base64 or base64url.
- To decode: paste Base64 in the bottom panel; the decoded bytes appear above (as text if printable, as a downloadable file if binary).
- Toggle Standard / URL-safe as needed. Standard uses
+and/; URL-safe uses-and_.
Base64 vs base64url — when each
Standard Base64 (RFC 4648): characters A-Z a-z 0-9 + /, padding with =. Used in MIME, most general-purpose contexts. base64url (RFC 4648 §5): replaces + with - and / with _, often omits padding. Used in JWTs, URL parameters, any place where + or / would need escaping.
Questions and answers
Is Base64 encryption?
No — it's encoding, not encryption. Anyone can decode Base64 instantly. Don't confuse "I encoded this so it's secure" with actual encryption.
Why is the Base64 33% bigger than the input?
Every 3 bytes of input become 4 characters of output (8 bits → 6 bits per output character). Plus a few = for padding. ~33% size increase is fundamental.
What if my Base64 has stray newlines or spaces?
The decoder strips whitespace automatically. Real-world Base64 (e.g. PEM certificates) is line-wrapped at 64 or 76 columns — that works fine.
Can I encode a 5 GB video?
Technically yes, but the output is ~6.6 GB of text — usually not what you want. Base64 is for small-to-medium binary embedded in text contexts.
Related tools
Get MiniMax Converter
Cross-platform desktop app. Linux free for non-commercial use; Windows & macOS one-time €20 license. No subscription, no telemetry, no account.