BMP Compressor

Reduce BMP file sizes by adjusting color depth and dimensions. BMP files can be quite large, but with smart compression you can significantly reduce their size while maintaining visual quality. For modern web use, consider converting to WebP or JPG formats.

Drop your BMP files here

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BMP Batch Upload
Max 50MB per file - Up to 10 files
Related Tools:
BMP to WebP BMP to JPG BMP to PNG BMP to ICO BMP Analyzer Image Resizer

How to Compress BMP Files

  1. Upload your BMP images by dragging and dropping or clicking the upload area. You can select up to 10 files at once for batch processing.
  2. Choose color depth: Lower color depths mean smaller files. 8-bit works well for most images, while 4-bit or 1-bit is ideal for simple graphics.
  3. Enable dithering if reducing colors on photos to maintain visual quality through pattern simulation.
  4. Optionally resize: Reducing dimensions further decreases file size. Use the Image Resizer for more control.
  5. Select output format: Keep as BMP or convert to PNG/JPG for additional compression.
  6. Compress and download: Click the compress button and download individual files or all as a ZIP archive.
Pro tip: For web use, convert BMP to WebP for the best compression. Use our BMP Analyzer to check your file details first.

Understanding BMP Compression

BMP Format

BMP (Bitmap) is an uncompressed raster image format developed by Microsoft. While it preserves exact pixel data, files are significantly larger than compressed formats. A typical 1920x1080 24-bit BMP is about 6MB, compared to 200KB in JPG or 100KB in WebP.

Color Depth

Color depth determines how many colors can be stored per pixel. 24-bit allows 16.7 million colors (true color), while 8-bit allows 256 colors using a palette. Reducing color depth is the primary way to shrink BMP files while keeping the format.

Color Depth Guide

24-bit

16.7 million colors. Original quality, no compression. Best for archiving or when you need perfect color accuracy. Consider converting to PNG for lossless compression.

16-bit

65,536 colors. Good balance for photos. Some color banding may appear in gradients. Reduces file size by about 33%.

8-bit

256 colors. Excellent for web graphics, icons, and images with limited colors. Reduces file size by 66%. Enable dithering for photos.

4-bit

16 colors. Best for simple graphics, diagrams, and logos with flat colors. Very small file sizes. Not recommended for photos.

1-bit

2 colors (black & white). Smallest possible size. Good for line art, text documents, and simple icons. Use dithering for photos.

Frequently Asked Questions

BMP is an uncompressed format that stores every pixel's color value directly. A 1920x1080 image at 24-bit color depth requires 1920 x 1080 x 3 bytes = 6.2MB. For smaller files, use our BMP to WebP converter or BMP to JPG converter.

Dithering is a technique that simulates colors not in the palette by mixing available colors in patterns. It helps maintain visual quality when reducing color depth, especially for photographs. For graphics with solid colors, you can disable dithering for cleaner edges.

For most purposes, yes. PNG offers lossless compression (smaller files, same quality), while JPG and WebP offer much smaller files for photos. Use BMP only when required by specific software. Try our BMP to PNG, BMP to JPG, or BMP to WebP converters.

Yes, reducing color depth means fewer available colors. For photos, 8-bit with dithering usually looks acceptable. For graphics and logos with limited colors, you can often use 4-bit without noticeable quality loss. Use our BMP Analyzer to preview results.

Each file can be up to 50MB in size, and you can upload up to 10 files at once. Since BMP files are large, this generous limit accommodates most use cases. For very large files, consider using the resize option to reduce dimensions first.

All compression happens directly in your browser for privacy. Files are never uploaded to our servers unless the browser doesn't support client-side processing, in which case they're temporarily stored and automatically deleted within 24 hours.