Convert BMP to JPG
A BMP stores every pixel uncompressed, which makes the files extraordinarily large — a single 12-megapixel image runs to roughly 36 megabytes. Converting to JPG typically reduces that by more than 95 percent with no difference you can see.
Files are decoded and re-encoded inside this browser tab. Nothing is uploaded — you can disconnect from the internet after this page loads and conversion still works.
If you are dealing with BMP files at all, it is usually because some old piece of software or scientific instrument produced them. Converting is almost always the right move.
How to convert BMP to JPG
- Drag your BMP files onto the box above, or click it to browse.
- Each file converts in place — no upload, no queue.
- Download them one by one, or grab the whole batch as a ZIP.
Why BMP files are so large
The BMP format, introduced by Microsoft in the 1980s, generally applies no compression whatsoever. It stores three or four bytes for every single pixel regardless of content. A plain white image takes exactly as much space as a detailed photograph of the same dimensions.
This was a reasonable trade when processors were slow and decompression was expensive. It is no longer a reasonable trade for anything, which is why almost nothing produces BMP by choice any more. Where you still encounter them is legacy Windows software, some scanner drivers, screenshot tools with old defaults, and laboratory or industrial cameras.
What the conversion costs
JPEG is lossy, so some detail is discarded. At the quality setting used here that is not perceptible in photographic content. Given that you are typically reducing a 36 MB file to under a megabyte, the trade is overwhelmingly worthwhile.
The exception is content with text or hard-edged graphics — a screenshot, a scanned document, a diagram. JPEG produces visible haloing around sharp edges, so convert those to PNG instead, which is lossless and still vastly smaller than BMP.
Transparency and other edge cases
Most BMP files have no alpha channel. Some 32-bit variants do, and where transparency is present it will be flattened onto white, because JPG cannot store it. If that matters, convert to PNG instead.
Very old or unusual BMP variants — run-length encoded, or with exotic bit depths — occasionally fail to decode, since browsers implement the common cases rather than the whole specification. If a file is rejected, opening and re-saving it in any image editor generally produces something readable.
Frequently asked questions
How much smaller will the JPG be?
Typically 95 percent smaller or more, because BMP applies no compression at all. A 36 MB BMP commonly becomes well under a megabyte.
Why is my BMP file so huge?
BMP stores three or four bytes per pixel with no compression. File size depends only on dimensions, not on image content.
Should I use JPG or PNG?
JPG for photographs. PNG for screenshots, scanned documents, diagrams or anything with text — JPEG produces visible artefacts around hard edges, and PNG is still far smaller than BMP.
My BMP will not convert. Why?
Browsers support the common BMP variants rather than the entire specification, so run-length encoded or unusual bit-depth files can fail. Opening and re-saving the file in any image editor usually fixes it.
Are files uploaded to a server?
No. Everything is processed locally in your browser — which matters here, since BMP files are large enough that uploading would be genuinely slow.