How it works
The BMP to PNG converter transforms Windows Bitmap (BMP) files into the modern, compressed PNG format. BMP is an uncompressed raster format with large file sizes — a 1920×1080 BMP is approximately 6MB. The same image as PNG is typically 500KB–2MB (lossless compression). This converter runs entirely in your browser.
BMP files are produced by Windows Paint (the default save format on older Windows versions), certain scanner drivers, legacy Windows software, and some embedded systems and industrial cameras. BMP is not accepted by most web upload fields and is impractical to email due to file size. PNG provides the same lossless quality at a fraction of the size.
How to use it: upload a BMP file. The tool decodes it and re-encodes it as PNG with full lossless compression. The original pixel data is preserved exactly — no quality loss. Download the PNG.
File size example: a 2000×1500 24-bit BMP ≈ 8.6MB. The same image as PNG with optimal compression ≈ 2–4MB (50–75% smaller). The compression ratio varies with image content — photos compress less than graphics, and images with large flat-color areas compress most aggressively.
Color depth: BMP supports 1-bit (monochrome), 4-bit (16 colors), 8-bit (256 colors), 16-bit, 24-bit, and 32-bit color. PNG supports all of these. The converter preserves the original color depth in the PNG output.
Transparency: 32-bit BMP files include an alpha channel which is preserved in the PNG output. 24-bit BMP files have no transparency; the PNG output will be fully opaque.
Privacy: BMP-to-PNG conversion runs in the Canvas API. No file is uploaded.
Frequently Asked Questions
- BMP (Windows Bitmap) stores pixel data with minimal compression. A 1920×1080px 24-bit BMP is approximately 6MB uncompressed. The format was designed as a simple, universal Windows internal format — not for efficient storage or transfer. PNG applies lossless compression and produces the same pixel data in 500KB–2MB.
- Yes, pixel for pixel. PNG uses lossless compression — the decompressed PNG pixels are mathematically identical to the original BMP pixels. There is no quality loss whatsoever.
- Paint uses BMP as its native format because it is a Windows system format that requires no codec or compression library — it is always available even in minimal Windows installations. Modern versions of Paint support PNG, JPG, and other formats; BMP persistence is a legacy default.
- Yes. Drop multiple BMP files into the upload area. Each is converted to PNG and available for individual download, or download all as a ZIP.