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Image Tools

BMP to PNG Converter

Convert old BMP bitmap files to PNG – the modern lossless format that every program, website and phone opens. Every pixel stays exactly the same, but the file typically becomes five to twenty times smaller, because PNG compresses the image while BMP stores it raw. Convert many files at once and download them as a ZIP.

  • Files stay on your device
  • No sign-up
  • Free to use

How to use BMP to PNG

  1. Drop BMP files onto the page.
  2. Click “Convert to PNG”.
  3. Check the size savings.
  4. Download the PNG files or a ZIP.

BMP to PNG features

Lossless

Identical pixels, colours and transparency.

Much smaller

Compressed instead of raw data.

Efficient encoder

UPNG with strong compression.

Batch

Convert many files at once and download a ZIP.

All common BMPs

1, 4, 8, 24 and 32-bit bitmaps.

Private

Converted in your browser; nothing is uploaded.

When to use BMP to PNG

  • Converting screenshots and scans from old software.
  • Preparing images for websites, which rarely accept BMP.
  • Shrinking archives of bitmap files.
  • Sharing images from industrial or medical devices.

BMP to PNG FAQ

Will the quality change?

No. PNG is lossless: the converted image has exactly the same pixels as the BMP.

Why is the PNG so much smaller?

BMP usually stores every pixel uncompressed. PNG applies filtering and DEFLATE compression, which is very effective on screenshots and graphics.

Are 32-bit BMPs with transparency supported?

Yes, where the browser decodes the alpha channel; the PNG keeps it.

Some BMPs fail. Why?

Rare variants – OS/2 bitmaps or compressed 16-bit files – are not decoded by browsers. Open them in an image editor and save them again.

Are my files uploaded?

No. Everything happens in your browser.

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BMP and PNG

BMP, the Windows bitmap format, dates from the 1980s. It stores images in the simplest possible way: a short header, an optional colour palette and then the pixel values row by row, usually without compression. That makes BMP easy to read for simple software and devices, but the files are large: a 1920 × 1080 screenshot takes about 6 MB.

PNG stores the same information losslessly but compressed. It first applies a filter to each row that predicts pixels from their neighbours, turning smooth areas into small numbers, then compresses the result with DEFLATE. Screenshots and graphics with large uniform areas shrink dramatically; photographs less so, but still noticeably.

The converter decodes the BMP with the browser’s image decoder and encodes the PNG with UPNG, a careful PNG encoder that often produces smaller files than the browser’s built-in one. Because both formats are lossless, the converted image is pixel-for-pixel identical.

If you need even smaller files and can accept some loss, convert the PNG to JPG or WebP afterwards, or use the PNG Optimizer to reduce colours.

All conversions run locally in your browser.

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