64
Developer Tool
Base64 Encoder / Decoder
Encode or decode Base64 text and files — URL-safe mode, line wrapping, real-time validation. 100% in-browser.
Mode
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Plain Text
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Base64 OutputWaiting
Encoded output will appear here
Options
URL-safe Base64 (RFC 4648 §5) — replaces + → - and / → _
Wrap lines every 76 characters (MIME standard)
Tip: Use URL-safe mode when embedding Base64 in URLs, JWT tokens, or filenames. Use line-wrap for PEM/MIME compatibility.
Common use cases
🔐
API authentication
HTTP Basic Auth encodes credentials as Base64. JWT tokens use URL-safe Base64 for header and payload.
📧
Email attachments (MIME)
MIME email encodes binary attachments in Base64 with 76-character line-wrapping so mail servers handle them safely.
🖼️
Inline images & data URIs
Embed images directly in HTML or CSS as data:image/png;base64,… to eliminate extra network requests.
🔗
URL-safe tokens
Store binary blobs (UUIDs, checksums) in URLs or cookies using URL-safe Base64 — no percent-encoding needed.
Common questions
Is Base64 encryption?
No. Base64 is an encoding scheme, not encryption. It transforms binary data into ASCII text so it can be safely transported over text-based protocols. Anyone can decode it — there's no key or secret involved.
Why does encoded text end with = or ==?
Base64 encodes 3 bytes at a time into 4 characters. If the input isn't divisible by 3, padding characters (=) are added to complete the group. URL-safe mode strips them since padding is optional in most contexts.
What's the size overhead?
Base64 encoding increases size by roughly 33% — every 3 bytes become 4 characters. Line-wrapping adds a small extra overhead. This is the expected trade-off for safe text transport.
Is my data safe using this tool?
Absolutely. Everything runs inside your browser using native JavaScript APIs (btoa, atob, FileReader). No data is ever sent to a server.
What's the difference between standard and URL-safe Base64?
Standard Base64 uses + and / characters which have special meanings in URLs. URL-safe Base64 (RFC 4648 §5) replaces them with - and _ so the output can be used in URLs, filenames, and HTTP headers without escaping.