Base64 Decoder

Decode Base64 to text online, including URL-safe strings — free and instant Base64 decoder.

About

About the Base64 Decoder

Decodes a Base64 string back into its original text, handling both the standard and URL-safe alphabets automatically.

Developers use it to inspect what's actually inside a Base64-encoded token, cookie or config value while debugging, and support teams use it to decode a value a customer pasted into a ticket. It's one of many free data tools on Toolapt, and like every tool here, it's free to use with no sign-up and no limit on how many times you run it.

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Guide

Using the Base64 Decoder

  1. 1

    Step 1

    Paste the Base64 string into the Base64 field.

  2. 2

    Step 2

    Click "Decode".

  3. 3

    Step 3

    Read the decoded text in the output box.

  4. 4

    Step 4

    Click "Copy" to copy the result, or "Clear" to start over.

  • Decodes both standard and URL-safe Base64 alphabets automatically
  • Restores missing = padding on its own, so trimmed values still decode
  • Correctly rebuilds full Unicode text, not just plain ASCII
  • Clear error messages when the input isn't valid Base64
  • Works entirely in your browser — nothing you paste is sent to a server
  • Free to use, with no sign-up and no limit on how many times you run it
  • Fully responsive, so it works just as well on a phone as on a desktop

Developers

Developers use the Base64 Decoder for inspecting what's actually inside an encoded token, cookie or config value while debugging.

API integrators

API integrators use the Base64 Decoder for checking the contents of an encoded Basic Auth header or webhook payload.

Support teams

Support teams use the Base64 Decoder for reading a value a customer pasted into a support ticket without needing to write any code.

Students learning encoding

Students learning encoding use the Base64 Decoder for seeing exactly what a Base64 string turns back into.

Examples

Base64 Decoder examples

3 worked examples

01

Decode a greeting

Decoding "SGVsbG8=" returns Hello, with those 5 bytes decoded from 8 Base64 characters.

02

Longer sentence

Decoding "SGVsbG8sIFdvcmxkIQ==" returns Hello, World!, all 13 characters restored with padding intact.

03

Missing padding restored

Decoding "SGVsbG8" with no = padding still returns Hello, since the tool adds the missing padding automatically before decoding.

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FAQ

Frequently asked questions

Quick answers to common questions about the Base64 Decoder.

What does the Base64 Decoder do?

It converts a Base64-encoded string back into its original, readable text.

Is the Base64 Decoder free to use?

Yes. It's free, with no sign-up, no watermark and no limit on how many times you use it.

Is my input safe when I use this tool?

Yes. Decoding happens entirely on your own device using your browser's built-in Base64 support — nothing you paste is sent to a server.

Does it matter if my Base64 uses - and _ instead of + and / ?

No. The tool automatically converts URL-safe characters ( - and _ ) back to the standard alphabet before decoding, so either form works.

What if my Base64 string is missing its = padding?

The tool adds the correct padding back automatically before decoding, so a trimmed value still works.

What happens if I paste something that isn't valid Base64?

You'll see a clear error message explaining that the text contains unexpected characters or an invalid length.

Can I use the Base64 Decoder on my phone?

Yes. The page is fully responsive and works on mobile, tablet and desktop browsers alike.

Does the Base64 Decoder have any limitations?

It's built for typical Base64 text payloads. It decodes to UTF-8 text, so Base64 representing arbitrary binary (like an image) won't display as meaningful text.

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