Base64 File Converter Online - Encode and Decode Files Locally
Encode a file as a Base64 data URL or decode Base64 into a downloadable browser Blob without uploading it.
About this tool
Selected files up to 20 MiB are read into a MIME-aware data URL. The decoder accepts a full data URL or raw Base64 and creates a temporary local download.
How to use
- Enter or select the source data.
- Run the tool locally with the required options.
- Review and copy or download the result.
Features
- File to Base64 data URL.
- Raw Base64 or data URL decoding.
- Local downloadable Blob output.
Common use cases
- Embed a small binary fixture.
- Inspect or restore Base64 file data.
- Create a local download from an API payload.
Common issues and tips
- File encoding is limited to 20 MiB and Base64 increases data size.
- Raw Base64 has no MIME information, so the selected fallback type and filename may need adjustment.
Privacy
Processing runs locally in your browser. Input and generated output are not uploaded to Tools12345.
Frequently asked questions
What is the encoding file limit?
20 MiB.
Is a data URL required for decoding?
No, raw Base64 also works.
Is the file uploaded?
No.