BMP files store every pixel uncompressed, which is why they are enormous. Converting to JPG typically shrinks them dramatically — right here in your browser.
BMP is Windows’ original bitmap format, and in most cases it applies no compression at all: a 12-megapixel image stores all 36 million bytes of pixel data as-is. Screenshots from old tools, scanner output, and exports from legacy Windows software arrive as multi-megabyte BMPs that email servers bounce and upload forms reject. JPG stores the same picture in a fraction of the space — a 90%+ reduction is normal for photographs.
Drop your BMP files onto the page and a Web Worker decodes them with the browser’s built-in bitmap decoder, then re-encodes each one as a high-quality JPEG (92%) at its original dimensions. The before and after sizes appear side by side, so you can see exactly how much space you saved. Nothing is resized and nothing is uploaded — the conversion has no server component, so even a folder of large scans processes quickly and privately.
JPG is lossy and has no transparency. For screenshots full of crisp text, diagrams, or anything you plan to edit repeatedly, convert BMP to PNG instead — it stays lossless and keeps edges perfectly sharp. For photographs headed to email, the web, or a document, JPG is the right call: the quality difference is invisible and the size difference is enormous.
Photographic BMPs typically shrink by 90% or more, since BMP stores pixels uncompressed. The tool shows exact before and after sizes for every file.
No — your browser decodes and re-encodes the file locally in a Web Worker. Your images are never uploaded anywhere.
JPG is lossy, but at the 92% quality this tool uses the difference is effectively invisible for photos. For text-heavy screenshots, BMP to PNG preserves edges better.
Yes. Queue as many as you like — three convert in parallel — and download the results individually or as one ZIP.