How much smaller will the JPG be than the BMP?

A lot. BMP stores three bytes for every pixel with no compression at all, so a JPG of the same picture is typically 10–20 times smaller at the default 90% quality, and smaller still if you lower the slider.

Does converting BMP to JPG lose quality?

JPG is lossy, so some fine detail is discarded. At 90% the difference is invisible for photographs and scans. Screenshots with small text show faint ringing sooner; keep those at 90% or above, or use BMP to PNG for a lossless result.

Can I convert .dib files too?

Yes. DIB (device-independent bitmap) is the same format under a different extension, and the converter accepts both .bmp and .dib.

Why does Windows Paint save BMP files?

Older versions of Paint defaulted to 24-bit bitmap, and the format is still offered in every version. Pick JPEG or PNG in Paint's Save As menu next time, or batch convert what you already have here.

Is my file uploaded anywhere?

No. The bitmap is decoded and re-encoded by your own browser using the Canvas API. It never leaves your device, and the tool keeps working offline once the page has loaded.

BMP to JPG Converter — Shrink Bitmaps 10×, Free

Convert BMP to JPG

Convert uncompressed BMP bitmaps into compact JPG photos, with a quality slider to balance size against detail. Everything runs in your browser, so nothing is uploaded.

No upload — runs in your browser

Batch convert & ZIP download

Free, no sign-up

Drop BMP, DIB files here

Choose files

Free: up to 5 files per batch · Files never leave your device · Paste from the clipboard works too

Private by design

Your files are processed by your own device using WebAssembly and your browser's built-in codecs. Nothing is uploaded, logged or stored.

Fast & offline-ready

No queue, no waiting for a server. Once the page has loaded it even works without a connection.

Works everywhere

Chrome, Edge, Firefox and Safari on Windows, macOS, Linux, Android and iOS. No app to install.

What a BMP file actually contains

A bitmap is the simplest image format there is: a short header followed by the colour of every pixel, row by row, with no compression. That simplicity made it the native image format of Windows from the start, and it is why the files are so large. A 24-bit BMP needs three bytes per pixel, so a 1920×1080 screenshot weighs about 6 MB and a 300 DPI scan of an A4 page passes 25 MB. JPG was designed for exactly this problem: it keeps what the eye notices and throws away what it does not.

Where BMP files still turn up

Windows Paint on older systems saved to 24-bit bitmap unless you changed the type, and many people never did.
Scanner and fax software, especially the utilities bundled with office printers, often defaults to BMP or offers it as the "uncompressed" choice.
Screen-capture tools from the Windows XP era, and some remote-desktop and test-automation software today, write bitmaps because they are trivial to produce.
Embedded and industrial systems: boot logos, instrument displays, machine-vision cameras and medical devices export BMP because the device has no library to compress with.
Game assets and clipboard dumps, where a texture or a pasted image ended up saved as .bmp or .dib.

Picking a quality

The Quality slider runs from 10% to 100% and feeds the browser's JPG encoder directly. The default of 90% is the safe choice: photographs, scans and anything with gradients come out indistinguishable from the bitmap. Dropping to around 80% roughly halves the file again with only slight softening at full zoom. Below 60% blocks and ringing appear around edges, fine for a thumbnail, wrong for print. Move the slider mid-batch and every file is redone at the new setting.

What to expect

Source bitmap	BMP size	JPG at 90%
1920×1080 screenshot	about 6 MB	300–600 KB
A4 scan at 300 DPI	about 26 MB	1.5–3 MB
12 MP camera frame	about 36 MB	2–4 MB

Exact figures depend on how much detail the image holds; each row shows the real output size before you download. Large files are limited by your device's memory, since the decoded bitmap and the new JPG both sit in RAM.

When JPG is the wrong choice

JPG has no transparency and softens hard edges, so line art, diagrams, pixel art and interface screenshots with small text are better served by BMP to PNG, which is lossless and still shrinks the file several times over. If the JPG is destined for a website, JPG to WebP trims it further, and the image compressor can tune any of them towards a target size. For the background on choosing between the three formats, read WebP vs PNG vs JPG.

How to convert bmp to jpg — step by step

Drop your BMP or DIB files onto the page, or click "Choose files" to pick up to 5 at a time.
Adjust the Quality slider if you like. 90% is the default; 75–85% gives noticeably smaller files for email or web use.
Each file converts as soon as it is added, with a progress bar and the finished JPG size shown in its row.
Download the JPGs one by one, or click "Download all as ZIP" to save the whole batch.

Frequently asked questions

How much smaller will the JPG be than the BMP?: A lot. BMP stores three bytes for every pixel with no compression at all, so a JPG of the same picture is typically 10–20 times smaller at the default 90% quality, and smaller still if you lower the slider.
Does converting BMP to JPG lose quality?: JPG is lossy, so some fine detail is discarded. At 90% the difference is invisible for photographs and scans. Screenshots with small text show faint ringing sooner; keep those at 90% or above, or use BMP to PNG for a lossless result.
Can I convert .dib files too?: Yes. DIB (device-independent bitmap) is the same format under a different extension, and the converter accepts both .bmp and .dib.
Why does Windows Paint save BMP files?: Older versions of Paint defaulted to 24-bit bitmap, and the format is still offered in every version. Pick JPEG or PNG in Paint's Save As menu next time, or batch convert what you already have here.
Is my file uploaded anywhere?: No. The bitmap is decoded and re-encoded by your own browser using the Canvas API. It never leaves your device, and the tool keeps working offline once the page has loaded.