Base64 Encoder & Decoder
Encode Unicode text or any file. Decode standard or URL-safe Base64 with strict validation, inspect the result and download the original bytes.
1. Provide input
No file selected. File bytes are encoded without changing the original format.
For large Base64 input, open a UTF-8 .txt or .b64 file. A preview is shown; processing uses the full file text.
Text input supports up to 500,000 characters. File encoding and decoding support 20 MiB of binary data. Base64 is a representation, not encryption.
2. Inspect & save
Large results show a bounded preview. Downloads always include the full output.
Decoded files download as binary attachments. The tool never executes or renders decoded HTML, scripts or other active content.
Ready. Try an example or enter your input.
Processing runs in your browser without a file upload or stored conversion history. Website ads and analytics follow our privacy information.
Using Base64 Encoder & Decoder
Convert text and binary data to or from Base64 in your browser. Review the encoding options, inspect the result and download the full output without uploading files for processing.
- Choose Encode or Decode. Encode UTF-8 text or a file; decode pasted Base64 or open a Base64 text file.
- Choose URL-safe alphabet, optional padding and line wrapping for encoding. Decoding accepts standard or URL-safe data, optional whitespace and Base64 Data URIs. Run the conversion.
- Inspect text or the binary hex preview. Copy supported text, switch operation with Use output as input, or download the complete Base64 or original bytes.
Example
Try Unicode example, then Use output as input and Decode to recover the original multilingual text and emoji. Try binary example: AP8BgA== decodes to bytes 00 ff 01 80. It is not valid UTF-8, so the tool shows hexadecimal and offers a binary download.
Questions & answers
Is Base64 encryption?
No. It is a reversible representation of bytes using printable characters. It does not hide or protect secrets.
Does it support emoji and other languages?
Yes. Text encoding uses UTF-8. Decoded text appears only if the bytes are valid UTF-8; otherwise a hexadecimal preview is shown. Unpaired Unicode surrogate characters are rejected rather than silently changed.
What is URL-safe Base64?
It replaces + and / with - and _. Padding can optionally be omitted. The decoder accepts either alphabet and rejects mixed standard and URL-safe symbols. Base64 URL-safe encoding differs from percent-encoding a URL.
Why is some Base64 rejected?
The decoder checks alphabet, placement and length of padding and zero unused trailing bits. Malformed or noncanonical input is rejected instead of guessing missing data. Unpadded input is accepted when its length and bits are valid.
Can I decode a Data URI?
Yes, with Accept Base64 Data URI prefix enabled. Only Base64 Data URIs are accepted. Its media type is shown as an untrusted hint; decoded HTML or scripts are never rendered or executed.
Do previews truncate my downloads?
No. Large text or Base64 results show a bounded preview while downloads contain complete output. Copy supports encoded output up to one million characters; reuse and decoded-text copy support up to 500,000 characters.
Which limits apply?
Text encoding supports up to 500,000 characters. File encoding and decoded bytes are limited to 20 MiB. Base64 text input is bounded to roughly 28 million characters including line breaks. Large Base64 input can be opened from a UTF-8 text file.
Are decoded file bytes preserved?
Yes. Binary downloads contain the exact decoded bytes, including a UTF-8 BOM if present. Filename and extension are your choice; downloads use a binary attachment type. Base64 adds roughly one third to file size before optional line wrapping.
Are my files uploaded?
No processing upload or stored conversion history is used. Conversion runs in a browser worker. Website ads and analytics follow the privacy information.
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