BMP to PNG Converter

BMP is an uncompressed format. Every pixel's color value is written to disk directly, row by row, with no compression of any kind. A 1920×1080 image saved as BMP occupies around 6 MB. The same image saved as PNG — also lossless, also preserving every pixel exactly — occupies 1–3 MB depending on content complexity, because PNG's DEFLATE compression algorithm finds and removes repetitive patterns in the pixel data. For images with flat color regions, solid backgrounds, and geometric shapes, the reduction is often 80–90%. For photographs with complex noise and texture, PNG compression is less efficient, but the BMP-to-PNG conversion is still lossless — no pixel changes.

AT USE BMP to PNG Converter processes the conversion server-side using ImageMagick. Upload a BMP file up to 20 MB, and download a PNG. No quality settings to choose — PNG is lossless and the conversion is exact. Your file is deleted from the server after download. No account required.

Why PNG instead of JPG for BMP files

BMP files most often appear in contexts where lossless quality matters: screenshots from Windows systems, line art from legacy design software, technical diagrams from engineering tools, scanned documents, and pixel art. For these image types, JPEG's lossy compression is the wrong choice — JPEG introduces artifacts at color transitions and blurs fine lines. PNG is the correct lossless replacement for BMP in every case where the image needs to look exactly like the BMP original. If you specifically need a smaller JPEG for a photographic BMP, that case is handled by the BMP to JPG converter.

Transparency

Standard 24-bit BMP files have no transparency. Some 32-bit BMP files include an alpha channel (supported via BITMAPV4HEADER and later), but in practice the vast majority of BMP files encountered are fully opaque. PNG supports a full alpha channel. If your 32-bit BMP contains transparency data, the converter preserves it in the PNG output. If your BMP is a standard 24-bit file, the PNG output is fully opaque, identical in pixel values to the original.

What changes during conversion

Nothing visible changes during BMP to PNG conversion — the pixel data is identical in both files. What changes is the file format container and the on-disk representation. BMP stores uncompressed rows of pixel data with a simple header. PNG stores the same pixel data compressed using DEFLATE and organized in a series of typed chunks. No quantization, no dithering, no color space conversion (both use sRGB by default).

File size after conversion

For flat-color images, screenshots, and line art, expect PNG files 60–90% smaller than the BMP source. A 6 MB BMP screenshot of a desktop becomes a 600 KB–1.8 MB PNG. For photographic BMPs with complex textures, expect 40–70% reduction. In no case does BMP to PNG conversion produce a larger file — DEFLATE compression always reduces file size compared to no compression.