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Online Base64 Converter

Convert text to Base64 or decode Base64 back to text. This tool uses UTF‑8, accepts Base64URL, fixes missing padding, and runs entirely in your browser (no uploads).

Category: Developer · URL: /tools/online-base64-converter.html
Decode accepts Base64URL ("-" and "_") and missing padding. Whitespace/newlines are ignored.
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Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Choose what you want to do (encode or decode), paste your input, then convert.

  1. Select Encode → Base64 or Decode → Text.
  2. Paste your value into the input box.
  3. Click Convert (or enable auto-convert).
  4. Use Copy Output to copy the result.
Keywords this page targets (natural cluster): online base64 converter, base64 encode online, base64 decode online, utf-8 base64 encoder, utf-8 base64 decoder, base64url to base64, base64url decode, remove whitespace from base64, fix base64 padding, atob btoa utf-8, convert string to base64, convert base64 to string, decode base64 json, base64 validator, base64 encoder decoder tool, base64url without padding decode, javascript base64 utf8, base64 for jwt payload
Secondary intents covered: Encode plain text into Base64 for transport or embedding, Decode Base64 content back into readable UTF‑8 text, Convert Base64URL (JWT-style) to normal Base64 and decode it, Validate whether an input is valid Base64 and see clear errors, Clean Base64 that contains whitespace or newlines, Copy the encoded/decoded result quickly for use in code or configs, Troubleshoot padding issues and illegal characters in Base64 strings, Decode Base64 JSON payloads (e.g., JWT parts) to inspect contents

FAQ

Does this tool support UTF‑8 (emoji, accents, non‑Latin text)?

Yes. Encoding and decoding are done using UTF‑8, so non‑ASCII characters work correctly.

What is Base64URL and can I decode it here?

Base64URL is the URL-safe variant used by JWTs ("-" and "_"). This tool accepts Base64URL input and fixes missing padding automatically.

Why does my Base64 sometimes end with one or two '=' characters?

Those are padding characters to make the length a multiple of 4. They can often be removed for Base64URL, but standard Base64 typically keeps them.

Is my data sent to a server?

No. Conversions run locally in your browser; the JavaScript does not make network requests.

Why do I get an “Invalid Base64 length” or “decoding failed” error?

The input likely contains illegal characters or has a length that can’t be valid Base64 (length mod 4 = 1). Remove extra characters or paste the full value.

Can I decode a JWT payload with this?

Yes. Paste the middle JWT segment (payload) and decode; it’s Base64URL JSON.

Does it ignore whitespace and line breaks in Base64 strings?

Yes. Spaces and newlines are removed before decoding.