$ encode --base64
base64 encoder / decoder.
Encode text or files to Base64, decode Base64 back to text, and download binary output. 100% client-side.
input
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0 / ∞ chars
upload a file to encode
output
Base64 encodes binary data into text format for safe transmission over text-based protocols like HTTP, email attachments, and data URIs in HTML/CSS.
No, Base64 is an encoding scheme, not encryption. Anyone can decode Base64 instantly. Never use it to protect sensitive data.
Yes, Base64 increases size by about 33%. For large files, consider sending binary directly or using compression before encoding.
How Base64 Works
Base64 converts binary data to 64 ASCII characters: A-Z, a-z, 0-9, +, and / (with = as padding). Every 3 bytes of input become 4 characters of output — that's why Base64 increases size by ~33%.
Common Use Cases
| Use Case | Why Base64? | Example |
|---|---|---|
| Data URIs | Embed images directly in HTML/CSS | data:image/png;base64,iVBOR... |
| Email attachments | SMTP is text-only protocol | MIME multipart encoding |
| JWT tokens | URL-safe header/payload encoding | eyJhbGci... |
| API auth headers | HTTP Basic Authentication | Authorization: Basic dXNlcjpwYXNz |
| JSON embedding | Binary data in JSON responses | {"image": "data:image/..."} |
Base64 vs Base64URL
Standard Base64: ABCDefgh+/==
Base64URL: ABCDefgh-_ (no padding, URL-safe chars)Base64URL replaces + → -, / → _, and removes = padding. Use it in URLs and filenames.
learn more in our detailed guide.
→ read the guide