Mr. Tools

How to

How to use Base64 Encode / Decode

A developer utility for Base64 encoding and decoding directly in the browser. It handles UTF-8 text, including non-ASCII characters, and lets you copy the result immediately. Enter text, convert it to Base64, restore it when needed, and copy the result in the same workspace.

Use Base64 Encode / Decode
Base64 Encode / Decode thumbnailBase64 Encode / Decode thumbnail

Use Cases

When to use it

  • Inspect Base64 values from APIs or configs
  • Encode non-ASCII text safely as Base64
  • Restore received Base64 text quickly
  • Check a Base64 value in an authorization header
  • Restore Base64 embedded in a config file
  • Verify that a Base64 string in your code is correct

Capabilities

What this tool can do

  • Encode text to Base64
  • Decode Base64 text
  • Copy the result or swap input and output
  • Safely encode UTF-8 strings including non-ASCII text
  • Swap input and output with one click
  • Copy the result to the clipboard immediately

Guide

How to use each screen area

Learn how to use each screen area, including settings, input, previews, results, and saving.

01 HOWTO

Input area

Use this screen area to prepare the source content and confirm the main controls before running the tool.

Screen showing Input area in Base64 Encode/DecodeScreen showing Input area in Base64 Encode/Decode

What this area does

  • Use this screen area to prepare the source content and confirm the main controls before running the tool.
  • Use this screen area to run the main action and compare the effect in the result area.
  • Use this screen area to check validation, error, or detail information before copying the result.
  • Use this screen area to copy, swap, export, or return to the related input area for another pass.

Where to use it

01
Character encoding

Use this screen area to prepare the source content and confirm the main controls before running the tool.

Screen showing where to use Character encoding in Base64 Encode/DecodeScreen showing where to use Character encoding in Base64 Encode/Decode
02
Input field

Use this screen area to run the main action and compare the effect in the result area.

Screen showing where to use Input field in Base64 Encode/DecodeScreen showing where to use Input field in Base64 Encode/Decode
03
Convert to Base64

Use this screen area to check validation, error, or detail information before copying the result.

Screen showing where to use Convert to Base64 in Base64 Encode/DecodeScreen showing where to use Convert to Base64 in Base64 Encode/Decode
04
Swap result

Use this screen area to copy, swap, export, or return to the related input area for another pass.

Screen showing where to use Swap result in Base64 Encode/DecodeScreen showing where to use Swap result in Base64 Encode/Decode

02 HOWTO

Input area

Use this screen area to run the main action and compare the effect in the result area.

Screen showing Input area in Base64 Encode/DecodeScreen showing Input area in Base64 Encode/Decode

What this area does

  • Use this screen area to prepare the source content and confirm the main controls before running the tool.
  • Use this screen area to run the main action and compare the effect in the result area.
  • Use this screen area to check validation, error, or detail information before copying the result.
  • Use this screen area to copy, swap, export, or return to the related input area for another pass.

Where to use it

01
Text input

Use this screen area to prepare the source content and confirm the main controls before running the tool.

Screen showing where to use Text input in Base64 Encode/DecodeScreen showing where to use Text input in Base64 Encode/Decode
02
Check encoding

Use this screen area to run the main action and compare the effect in the result area.

Screen showing where to use Check encoding in Base64 Encode/DecodeScreen showing where to use Check encoding in Base64 Encode/Decode
03
Choose conversion direction

Use this screen area to check validation, error, or detail information before copying the result.

Screen showing where to use Choose conversion direction in Base64 Encode/DecodeScreen showing where to use Choose conversion direction in Base64 Encode/Decode
04
Prepare restore

Use this screen area to copy, swap, export, or return to the related input area for another pass.

Screen showing where to use Prepare restore in Base64 Encode/DecodeScreen showing where to use Prepare restore in Base64 Encode/Decode

03 HOWTO

Convert and restore area

Use this screen area to check validation, error, or detail information before copying the result.

Screen showing Convert and restore area in Base64 Encode/DecodeScreen showing Convert and restore area in Base64 Encode/Decode

What this area does

  • Use this screen area to prepare the source content and confirm the main controls before running the tool.
  • Use this screen area to run the main action and compare the effect in the result area.
  • Use this screen area to check validation, error, or detail information before copying the result.
  • Use this screen area to copy, swap, export, or return to the related input area for another pass.

Where to use it

01
Convert to Base64

Use this screen area to prepare the source content and confirm the main controls before running the tool.

Screen showing where to use Convert to Base64 in Base64 Encode/DecodeScreen showing where to use Convert to Base64 in Base64 Encode/Decode
02
Restore Base64

Use this screen area to run the main action and compare the effect in the result area.

Screen showing where to use Restore Base64 in Base64 Encode/DecodeScreen showing where to use Restore Base64 in Base64 Encode/Decode
03
Swap input and output

Use this screen area to check validation, error, or detail information before copying the result.

Screen showing where to use Swap input and output in Base64 Encode/DecodeScreen showing where to use Swap input and output in Base64 Encode/Decode
04
Review input

Use this screen area to copy, swap, export, or return to the related input area for another pass.

Screen showing where to use Review input in Base64 Encode/DecodeScreen showing where to use Review input in Base64 Encode/Decode

04 HOWTO

Result and copy area

Use this screen area to copy, swap, export, or return to the related input area for another pass.

Screen showing Result and copy area in Base64 Encode/DecodeScreen showing Result and copy area in Base64 Encode/Decode

What this area does

  • Use this screen area to prepare the source content and confirm the main controls before running the tool.
  • Use this screen area to run the main action and compare the effect in the result area.
  • Use this screen area to check validation, error, or detail information before copying the result.
  • Use this screen area to copy, swap, export, or return to the related input area for another pass.

Where to use it

01
Copy result

Use this screen area to prepare the source content and confirm the main controls before running the tool.

Screen showing where to use Copy result in Base64 Encode/DecodeScreen showing where to use Copy result in Base64 Encode/Decode
02
Check restored text

Use this screen area to run the main action and compare the effect in the result area.

Screen showing where to use Check restored text in Base64 Encode/DecodeScreen showing where to use Check restored text in Base64 Encode/Decode
03
Convert again

Use this screen area to check validation, error, or detail information before copying the result.

Screen showing where to use Convert again in Base64 Encode/DecodeScreen showing where to use Convert again in Base64 Encode/Decode
04
Edit input

Use this screen area to copy, swap, export, or return to the related input area for another pass.

Screen showing where to use Edit input in Base64 Encode/DecodeScreen showing where to use Edit input in Base64 Encode/Decode

Notes

Notes

Important points are grouped with reasons so you can make decisions before using the tool.

Things to check

Confirm the character encoding first

The result can change when the text includes Japanese characters or special symbols. Confirm whether you need UTF-8, Shift_JIS, or another encoding before converting.

Things to check

Make sure the Base64 string is complete before decoding

If characters are missing at the end or extra characters are mixed in, the original text cannot be restored correctly. Check that the copied Base64 text is complete.

Note

File-to-Base64 conversion is not supported

This page is for text strings only. Binary data and image file conversion are not supported. Use a different tool if you need to convert files.

FAQ

Questions about Base64 Encode / Decode

Questions that make decisions easier before use are summarized first.

Can it encode non-ASCII text?

Yes. It treats the text as UTF-8, so it can encode text beyond plain ASCII.

Can it convert files to Base64?

No. This page is for text conversion only and does not handle files.

Can it handle very long strings?

It can process strings within the limits of the browser. Very long strings may take a moment to convert.

Can it convert binary data or image files?

This page is for text strings only. Binary data and image file conversion are not supported.

Can it decode a Base64 string that contains line breaks?

Try removing the line breaks before decoding. Their presence may affect the decoded result.

Can I copy the output directly?

Yes. The result can be copied to the clipboard with one click.

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