Free Online Base64 Encoder

Base64 encoding converts arbitrary bytes or UTF-8 text into a 64-character ASCII alphabet for safe embedding in JSON, JWTs, basic-auth headers, and data URIs.

Your data is processed entirely in your browser and never sent to any server.

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How to Use This Developer Tool

  1. Paste text into the input area.
  2. Toggle URL-safe if you need the URL-safe alphabet.
  3. Read the encoded output in the right panel.
  4. Click Copy to send the Base64 string to your clipboard.

What Is a Base64 Encoder?

Base64 (RFC 4648) is the encoding you reach for whenever binary data needs to travel through a text-only channel — JSON request bodies, JWT payloads, HTTP basic auth, email attachments, inline `data:` images in HTML or CSS. It is not encryption: anyone with the encoded string can decode it back to bytes.

This encoder handles Unicode correctly (UTF-8 first, then Base64), supports the URL-safe variant (`-` and `_` substituted for `+` and `/`) for use in URL paths, and lets you toggle padding. All processing happens in your browser, so tokens, API keys, and small files you don't want uploaded stay local.

Frequently Asked Questions

What is Base64 encoding?
Base64 converts binary data to ASCII text using 64 characters (A-Z, a-z, 0-9, +, /). It's used to embed binary in JSON, emails, and URLs.
When would I use Base64?
Embedding images in HTML/CSS, storing binary in JSON, encoding credentials, or sending binary data through text-only channels. Data URIs use Base64.
Does it increase size?
Yes, Base64 increases size by ~33%. 3 bytes become 4 characters. It's for compatibility, not compression.

Published by the WeGotEveryTool team. We build and test every tool in-house and update pages when the underlying spec, formula, or recommendation changes.

Reviewed: May 2026. Disclaimer: this tool is provided as-is for general informational use. For decisions with material consequences (medical, legal, financial, security) verify results against a qualified professional source.

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