Developer tool
Convert text and files to Base64 and back
Encode text or a file to Base64, decode Base64 to text or a file, and use Base64URL. Conversion stays in your browser.
Convert UTF-8 text, files, and Base64URL locally. Nothing is uploaded to NEXNARA.
- Runs locally
- No uploads
- Instant
- Free
Base64 is about 33% larger than the original bytes. Files over 10 MB may slow the tab. This page blocks files over 32 MB.
How it works
- 01 Paste your data
- 02 Run the action
- 03 Copy the result
Why NEXNARA
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Private
Your data stays in your browser.
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Instant
Results appear immediately.
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No uploads
Nothing is sent to a NEXNARA server.
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Works anywhere
No installation required.
Learn more
What is Base64?
Base64 turns binary data into ASCII text using A–Z, a–z, 0–9, +, and /. It is an encoding, not encryption. Anyone can decode it without a key.
What is Base64URL?
Base64URL is the same encoding with + changed to -, / changed to _, and padding often omitted. Tokens and some URLs use it. This is not a JWT decoder.
Why is Base64 larger?
Every 3 bytes become 4 ASCII characters, so the result is about one third bigger, plus optional padding. That extra size is expected, not compression.
File to Base64
Choose or drop a file to encode it in the browser. You can copy raw Base64 or a data URL. Decode a Base64 string or data URL back into a downloadable file. The file is not uploaded.
Base64 vs URL encoding
URL encoding (percent encoding) makes text safe inside a URL. Base64 encodes arbitrary bytes as ASCII. Use the URL Encoder for query values and links; use this page for text, files, and data URLs.
How to use it
In Text mode, paste text and press Encode, or paste Base64 and press Decode. Swap exchanges the two boxes. File mode encodes one file. To file turns Base64 or a data URL into a download. Copy and Download .txt use the current result.
Unicode support
Text encoding uses UTF-8 bytes, so Korean, Japanese, Chinese, Arabic, Hindi, and emoji round-trip correctly. Plain btoa on a Unicode string is not used.
Common uses
Use Base64 for data URLs, inspecting encoded strings, or moving bytes through text-only channels. Do not treat it as a way to hide secrets.
Privacy
Text and files stay in the browser. Nothing is uploaded to NEXNARA and nothing is saved in cookies, local storage, or a database.
FAQ
Is Base64 encryption?
No. Base64 is an encoding. Anyone can decode it. Do not use it to protect passwords or secrets.
Can Base64 encode Unicode?
Yes. This tool converts text to UTF-8 bytes first, then to Base64, so non-English text and emoji work.
Can I convert a file to Base64?
Yes. Open File mode, choose or drop one file, then Encode. You can copy raw Base64 or a data URL. The file is not uploaded.
Why is Base64 larger than the original?
Base64 stores 6 bits per character, so 3 bytes become 4 characters — about 33% more, plus padding.
What is Base64URL?
A URL-safe alphabet: - instead of +, _ instead of /, and often no = padding. Encode and decode it here. JWT payloads are not decoded as tokens.
Is my data uploaded?
No. Text and files are converted in your browser only. There is no server upload and no external API.
Can I decode Base64 locally?
Yes. Decode runs in this tab. For binary data, use To file instead of Text decode.
What happens with invalid Base64?
The tool shows Invalid Base64 and does not crash. Spaces are ignored. Missing padding is filled in. Broken input such as a truncated string is rejected.