Base64 to BMP
Paste a Base64 string or a data:image/bmp;base64, URI below and click Decode Base64 to BMP. The decoder checks the file signature, shows a preview and lets you download the result as a real .bmp file.
How to convert Base64 to BMP online
- Paste the Base64 value into the input box. Data URIs, whitespace and line breaks are handled automatically.
- Press Decode Base64 to BMP.
- Check the preview and the detected file type, dimensions and size.
- Click Download to save the .bmp file.
Important notes about the decoder
- The decoder detects the real file type from the decoded bytes (magic number). If your string is not actually BMP, you will see the real type and can still download it.
- Invalid characters are reported instead of silently producing a broken file. If decoding fails, try the Base64 repair tool.
- Nothing is uploaded: the data is decoded locally by your browser, so even confidential documents stay on your device.
About BMP
BMP is the native Windows bitmap format. Pixels are usually stored uncompressed, so files are large but trivial to read and write, which keeps BMP popular in embedded systems and legacy software.
Because BMP is uncompressed, encoding it to Base64 produces a very long string. If you only need to display the image on a web page, converting it to PNG first will make the Base64 output dramatically shorter.
| Developed | Microsoft, Windows 1.0+ |
|---|---|
| Compression | Usually none (optional RLE) |
| Transparency | Limited (32-bit variants) |
| Animation | No |
| File signature | 42 4D ("BM") |
Frequently asked questions
How do I convert Base64 to BMP?
Paste the Base64 string into the box above and click "Decode Base64 to BMP". You can preview the result and download it as a .bmp file.
Why is my Base64 BMP not displaying?
Usually the string is truncated, contains URL-safe characters, or was double-encoded. The decoder reports the exact problem; the Base64 repair tool can fix most of them automatically.
Do I need to remove the data URI prefix?
No. The decoder strips "data:...;base64," automatically and uses the MIME type from it as a hint.
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