Base64 Encoder / Decoder
Encode and decode Base64 strings (UTF-8 safe). Paste text, get output instantly. No upload.
Last updated: April 2026 · Runs in your browser · No sign-up
Frequently Asked Questions
What is Base64 used for?
Embedding binary data in text contexts: data URIs in HTML/CSS, JWT payloads, email attachments (MIME), Basic-Auth headers, API tokens.
Is Base64 encryption?
No — it's encoding, not encryption. Anyone can reverse it. Never use Base64 to protect secrets.
URL-safe Base64 — what's the difference?
Standard Base64 uses '+' and '/'. URL-safe variant swaps those for '-' and '_' so the string can be used in URLs and filenames without escaping.
Does Base64 handle UTF-8 correctly?
This tool encodes UTF-8 properly. The native browser btoa() is limited to Latin-1 — we use TextEncoder for full Unicode support.
How much bigger is Base64 vs. raw bytes?
About 33% larger (4 characters per 3 input bytes, rounded up). That's why large binary payloads are usually compressed or sent as binary-safe multipart instead.