A walkthrough, end to end.
- 1
Type or paste text into the input.
- 2
Pick encode (text → Base64) or decode (Base64 → text).
- 3
The result updates instantly.
Base64
Base64 represents binary data as ASCII by mapping every 6 bits to one of 64 printable characters (A–Z, a–z, 0–9, +, /). Output is a 4/3 size increase.
What you can do with this.
Embedding small images
Inline a tiny PNG in CSS as a data URI.
Email attachments
MIME messages encode binary attachments in Base64.
JWT tokens
JWTs use Base64URL for header/payload.
API debugging
Decode Base64 fields in HTTP responses.
Saving keys safely
Store binary keys as text in config files.
Signed URLs
Inspect tokens or signatures encoded in Base64.
Quick config copy
Encode multiline configs into a single line.
Base64 2026 — what's current
Standard since RFC 4648; calculator wins for instant client-side use.
Frequently asked.
Yes — input is encoded as UTF-8 before Base64.
Toggle URL-safe mode to use - and _ instead of + and /.
No. Encoding/decoding runs locally.
Invalid Base64 returns an error message.