JPG to BMP Converter
Convert JPG to BMP in your browser. JPG files usually come from cameras, phones, scanners and almost every app that saves photos; BMP is the better fit for legacy software and embedded systems that require it. You get an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
JPG expected · other image formats also work
How to use JPG to BMP
- 1
Add your JPG files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the BMP is written uncompressed. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .bmp files one at a time or together as a ZIP.
Why use Aback Images for jpg to bmp
Where the BMP goes next
BMP opens in every operating system and browser.
BMP next to JPG
The BMP is written uncompressed, so expect it to be several times larger than the JPG, which stores lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution.
No new artefacts
JPG is already lossy, since it stores lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; the BMP keeps the decoded pixels uncompressed, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
JPG vs BMP
What changes from JPG to BMP
Encoding: the JPG uses lossy DCT coding in 8×8 pixel blocks, with colour usually stored at half resolution; BMP uses usually none; RLE for some 4 and 8-bit files, and the download is an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency.
Bit depth: 8 bits per channel in the JPG; BMP allows 1, 4, 8, 16, 24 or 32 bits per pixel, and the BMP written here has 24 or 32 bits per pixel.
Colour: YCbCr shown as RGB, greyscale, or CMYK from print software in the JPG; BMP supports RGB or an indexed palette, written here as 8-bit sRGB.
Metadata: the JPG can carry EXIF (camera, date, GPS), XMP, IPTC and an ICC profile in APP segments; BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers), but nothing is copied across.
About JPG
JPEG is the universal photo format. It compresses by discarding fine detail the eye is least sensitive to, which makes photos small but blurs sharp edges and text if pushed too far.
A JPEG starts with the bytes FF D8 and is a run of marker segments: APP1 carries EXIF and often a thumbnail, APP2 an ICC profile, DQT the quantization tables that decide the quality, and SOS the compressed scan, which ends at FF D9.
JPG files usually come from cameras, phones, scanners and almost every app that saves photos.
About BMP
BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.
A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.
When converting JPG to BMP makes sense
BMP is the better choice for legacy software and embedded systems that require it, while JPG suits photographs that need to open anywhere.
BMP strengths: No compression artifacts; Read by very old and very simple software. Drawbacks to weigh: Enormous files; Poor support for transparency; No metadata.
Limitations
- JPEG artefacts already in the file, such as blocking near edges and smeared colour, are kept as pixels: a lossless target preserves them faithfully rather than removing them.
- A BMP is uncompressed, about 3 bytes per pixel, or 4 with transparency, so expect a large file.
- Some older programs ignore the alpha channel of a 32-bit BMP and show transparent areas as black or white.
More conversions
Related tools
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Convert JPG to AVIF in your browser, ready for maximum compression on modern websites. Batch, private, no uploads.
Convert JPG to HEIC in your browser, a HEIF file with JPEG compression inside. Batch, private, no uploads.
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Frequently asked questions
Does converting JPG to BMP lose quality?
BMP is written uncompressed, so the pixels are stored exactly as decoded. Artefacts already in the JPG stay, but nothing new is lost.
Which apps open BMP files?
Every operating system and browser.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.