BMP to PNG Converter
Convert BMP images to PNG in your browser. Lossless, nothing uploaded, and the file usually ends up far smaller.
This BMP to PNG converter re-encodes a bitmap as a PNG without sending it anywhere. Drop one .bmp file on the upload area or click to pick it, press Convert to PNG, and the page reports the new size before you download. A 28.18 KB three-band test bitmap came back as 476 B, because PNG compresses flat colour that an uncompressed bitmap stores byte by byte.
Drop your image here
or click to select a file
Supported formats: PNG, JPG, WebP, GIF, BMP
Higher quality = larger file size
Conversion complete!
New file size:
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About BMP to PNG Converter
Everything happens inside the tab. The file you choose is read with FileReader, decoded by the browser's own image decoder, drawn onto a canvas the same width and height as the original, and encoded as PNG. Nothing is uploaded, so the conversion works with the network disconnected once the page has loaded, and the file never becomes someone else's copy.
Because both BMP and PNG are lossless raster formats and the canvas keeps the original pixel dimensions, the visible image is unchanged; no quality slider is shown on this page, because PNG has no quality setting; that control only appears when the target format is JPEG or WebP. The size usually falls sharply all the same: an uncompressed 24-bit bitmap stores three bytes per pixel, while PNG applies filtering and DEFLATE compression, and the page prints the resulting size under Conversion complete. The download keeps your original file name with .png in place of .bmp.
Its limits are worth stating plainly. One file at a time: the picker takes a single file and dropping several converts only the first, so there is no batch mode and no ZIP of results. The upload accepts image/* but then checks that the file's reported type contains bmp, so a bitmap your system labels differently is refused with a message asking for a BMP file. Very large bitmaps are limited by the memory of the tab rather than by any cap the page sets, and an image the browser cannot decode produces a conversion error rather than a broken file.
Converting to PNG does not create transparency. PNG can carry an alpha channel, but this tool copies what the decoder gives it; a bitmap with a white background becomes a PNG with a white background, and removing that background is a separate editing job. Nor does the tool resize, crop, strip metadata or change colour profiles - it converts the container and leaves the picture alone.
Use Cases
How to use
Click the upload area to open the file picker, or drag one .bmp file onto it.
Check the preview: the thumbnail, the file name and the original size appear beside it once the file is accepted.
Press Convert to PNG and wait a moment while the browser decodes and re-encodes the image.
Read the New size figure under Conversion complete to see how much the PNG saved over the bitmap.
Press Download PNG; the file is saved with the original name and a .png extension.
Press Convert another to clear the page and start on the next bitmap.
Pro Tips
- Convert one file, press Convert another, then pick the next. The picker reads a single file and dropping a group converts only the first one, so a folder of bitmaps has to be worked through one at a time.
- No quality slider appears here, and that is correct: PNG is lossless and has no quality parameter, so the control stays hidden. It only shows up on the converters whose target is JPEG or WebP.
- Read the New file size line under Conversion complete before downloading. A 28.18 KB bitmap of flat colour bands came back as 476 B here, while a bitmap of a photograph shrinks far less, because PNG compresses repeated rows better than photographic noise.
- The downloaded file keeps the original base name and swaps the extension, so scan-014.bmp becomes scan-014.png. Rename before converting if you want a different name; the tool offers no field for it.
- If a file is refused with a message asking for a BMP, the browser did not report its type as a bitmap. Check the real extension, and be aware that a file renamed to .bmp without being re-encoded is not a bitmap.
Troubleshooting
The page says to select a BMP file even though the file ends in .bmp.
The check reads the type the browser reports, not the extension, so a file renamed to .bmp without being re-encoded is rejected. Open it in an image viewer and export it as a bitmap, or use the converter that matches its real format.
I dropped several bitmaps and only one was converted.
That is the tool's limit: both the drop handler and the file picker take a single file. Convert the first, press Convert another, and repeat for each bitmap; there is no batch mode on this page.
Conversion fails on a very large bitmap.
Decoding an uncompressed bitmap and holding a canvas of the same size needs several bytes per pixel of memory, and a tab can run out on a phone or an older machine. Try the same file in a desktop browser, or reduce the image's dimensions first.
The PNG still has the white background I wanted removed.
Format conversion does not change pixels. The converter reproduces what the bitmap contained, so a white background stays white. Making a background transparent requires editing the image itself, which this page does not do.
Frequently Asked Questions
Yes, with no account, no key, no watermark and no cap on how many files you convert one after another. There is nothing to sell here because there is no server cost: the conversion is JavaScript running on your own machine, and the page only has to be loaded once.
No. The file is read locally with FileReader, decoded by your browser and re-encoded with the canvas API; no request carries the image off the page. Once the page has loaded you can disconnect from the network and the conversion still works, which is the simplest way to confirm it for yourself.
No. Both are lossless raster formats and the canvas keeps the original width and height, so the visible image is the same. The file usually gets much smaller anyway: a 28.18 KB test bitmap of flat colour bands came out of this page as a 476 B PNG, because an uncompressed bitmap stores raw bytes per pixel while PNG filters and compresses the rows.
Not on this page. The file picker takes one file, and dropping a group converts only the first, so there is no batch mode, no queue and no ZIP download. Convert one, press Convert another, and repeat; for a large folder, a desktop tool or a command-line converter is the right instrument.
Only if the source already had transparency. PNG supports an alpha channel, but this converter copies the image it is given rather than deciding what should be see-through, so a bitmap with a white background becomes a PNG with a white background. Removing a background is an editing job, not a format conversion.
The page sets no limit; the ceiling is the memory the browser tab can use for the decoded image and the canvas. Uncompressed bitmaps are large, so a very high-resolution scan can exhaust that on a phone and fail with a conversion error. If that happens, try it on a desktop browser.
For almost every modern use, no. BMP normally stores pixels uncompressed, so files are large, and browsers, chat apps and CMS uploaders often refuse them. PNG is lossless like BMP, supports transparency, and compresses; the one thing BMP has going for it is that its structure is trivial to read, which matters to a few old programs.
Yes. Tap the upload area, pick the bitmap from your files or photos, and download the PNG in the same way you would any other file. The conversion still happens on the device, so it is bounded by the phone's memory rather than by an upload limit.
The page checks that the browser reports the file's type as a bitmap before accepting it. A file that has been renamed to .bmp without being re-encoded, or one your system reports under a different type, is refused with a message asking for a BMP file. Open it in an image viewer and re-export it as a bitmap.
The original base name with .png in place of the old extension, so holiday.bmp is saved as holiday.png. There is no field for renaming; if you need a different name, rename the source before converting or the download afterwards.