OneTools Online

Base64 Decode & Encode

Input
Input Character set
Output

Base64 Encoder & Decoder - Encode and Decode Online

Supports 40+ Character Encodings

Full compatibility with UTF-8, GB18030, Windows codings and international standards
Windows-(1250...1256)
ISO-8859-(1...16)
EUC-JP
EUC-KR
KOI8-R
KOI8-U
ISO-2022-JP
ISO-2022-KR
Shift_JIS
Big5
MacRoman
HZ
UTF-8
ASCII
GB18030
UTF-16
UTF-16BE
UTF-16LE
UTF-32
UTF-32BE
UTF-32LE
UCS-2
UCS-2BE
UCS-2LE
UCS-4
UCS-4BE
UCS-4LE
CP437
CP850
CP858

How to Use

  1. Paste the text you want to convert

    Type or paste into the input box. This page converts text — it has no file upload.

  2. Pick a character encoding and a direction

    Choose the source character set (UTF-8, UTF-16, Shift_JIS, GB18030, the ISO-8859 family and more), then switch between Encode and Decode. The output updates as you type.

  3. Copy or save the result

    Copy the output to your clipboard, or save it as a .txt file named with a timestamp. Everything runs in your browser.

Security & Privacy

Client-side processing (No data upload)
Data never leaves your device
End-to-end SSL encryption

Cross-Platform Compatibility

Works perfectly on PC, mobile & tablets
No installation required
100% free with no limits

Frequently Asked Questions

Why does my decoded text come out as garbled characters?
Almost always a character-encoding mismatch. Base64 carries bytes only — it does not record which encoding the original text used. Text encoded as Shift_JIS and decoded as UTF-8 produces mojibake. Set the character coding to the one used for encoding and decode again.
Does it support UTF-8, UTF-16 and legacy encodings?
Yes. The selector covers UTF-8, UTF-16 and UTF-32 in both byte orders, UCS-2 and UCS-4, the ISO-8859 and Windows-125x families, and CJK sets including Shift_JIS, EUC-JP, EUC-KR, GB18030, Big5 and ISO-2022-JP/KR.
Can I convert an image or a PDF to Base64 here?
No. This page converts text only and has no file upload. To Base64-encode a binary file, use a dedicated file converter or your language's standard library.
Is the text I paste sent anywhere?
No. Encoding and decoding run entirely in your browser using JavaScript's TextEncoder and btoa/atob. Nothing you type is uploaded or stored.

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