BMP to GIF Converter

What Is the BMP to GIF Converter?

This tool converts a BMP image to GIF entirely in your browser -- the file is decoded, redrawn onto a canvas, quantized down to GIF's 256-color indexed palette, and LZW-compressed into a real .gif file, all without ever being uploaded to a server. If your source image has 256 or fewer unique colors (typical for logos, screenshots, and flat-color graphics), the palette is built from its exact colors with no quality loss; a genuinely photographic image with more colors is automatically reduced to a fixed 256-color palette instead.

How to Use This Tool

Click the upload area and choose a BMP file. The converted preview appears immediately; click Download to save it as a real .gif file.

Need to go the other way? Use the GIF to BMP tab above, or open the GIF to BMP converter directly.

Why Convert BMP to GIF

GIF is still the format of choice anywhere near-universal, decades-old compatibility matters more than color accuracy -- old forums, certain CMS upload filters, and some embed widgets accept GIF specifically. Its 256-color palette makes it a poor fit for photographs (expect visible color banding on gradients and skies), but a strong one for logos, icons, and simple flat-color graphics, which compress to it with no visible loss at all.

Why This Direction Often Saves a Lot of Space

BMP files are typically uncompressed, so their size is essentially width times height times bytes per pixel. A 24-bit BMP uses 3 bytes per pixel, while a GIF stores one palette index per pixel and then compresses those indexes with LZW. For graphics with large runs of identical pixels, such as diagrams and screenshots, the difference can be dramatic. As a hypothetical example, an 800x600 24-bit BMP is about 1.44 million bytes (800 x 3 x 600, plus a small header). The same picture as an exact-palette GIF might be a small fraction of that, depending on how repetitive the image is. The tool shows the output size so you can see the actual result.

Photographs Are a Different Story

A photographic BMP contains many thousands of distinct colors. Because a GIF holds at most 256, the tool maps each pixel to the nearest color in a fixed 8-8-4 level grid of red, green and blue. There is no dithering, so smooth transitions such as skies or skin tones can show flat bands. The file may also not shrink as much as you hope, since photographic noise compresses poorly with LZW. If you have a photo in BMP, converting to JPG or PNG is usually a better choice unless GIF is specifically required.

Transparency Rarely Matters Here

Standard BMP files do not carry transparency, so you do not normally lose anything on that front. Some BMP variants store an extra alpha byte per pixel, and the browser may or may not honor it when decoding. The GIF this tool writes ignores alpha in any case, so treat the output as a fully opaque image.

Worked Example

You have a 640x480 BMP of a simple bar chart with a white background, a few colored bars and black text. The distinct color count is small, so the palette is exact and the GIF looks identical to the BMP while being much smaller. If the same chart had been saved with a photographic background, the count would exceed 256 and the fixed grid would be used, changing some shades.

Things to Keep in Mind

• The output has the same width and height as your BMP. Nothing is scaled.
• The result is one still frame; the tool does not create animations.
• Very large BMP files take longer because everything runs in your browser and the pixels must be counted and compressed.
• Keep your BMP as the master if you might need full 24-bit color later.

Frequently Asked Questions