Convert BMP to JPG
A 6 MB bitmap from Paint or a scanner becomes a 300 KB JPG you can actually email. Whole folders at once, quality slider, in your browser — no upload.
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The file came out of Paint, a scanner driver or a program that predates the web, and now it is in the way: 6 MB for one screenshot, 24 MB for a single scanned page, and an upload form that only lists .jpg, .png and .pdf. BMP stores every pixel uncompressed. That is why the number is so big, and why changing the format fixes it so completely.
Paint can Save As JPEG, but one file at a time and with no say over quality. Drop the whole folder here instead: every .bmp comes back as a JPG typically 10 to 20 times smaller, with the quality slider in your hands. The browser decodes and re-encodes on your own machine, so a 30 MB bitmap costs nothing in upload time.
Two settings worth deciding before you generate. A scanned page of small type wants a higher quality number than a photo, and a bitmap of pure black line art on white is better off as PNG than JPG. Both are one click in the settings panel, and the sections below say when each applies.
How it works
Output is preset to JPG. The only decision left is the quality number, and it depends on what is in the bitmap.
Add the .bmp files
Drag them in, click to browse, or paste a bitmap from the clipboard with Ctrl+V. Select the files inside a folder rather than the folder itself; there is no file count and no upload cap, only your device's memory.
Set the quality for the content
JPG is already selected and the slider sits at 82, right for photos and interface screenshots. Push it to 90 or above for scanned documents with small text, or switch the format to PNG for black-and-white line art.
Generate, compare, download
Click Generate images. Each card shows the BMP size next to the new JPG size, and Compare opens a before/after slider. Download one at a time or the whole batch as a .zip.
Why a BMP is 6 MB and the JPG is 300 KB
A 24-bit BMP stores three bytes per pixel and compresses nothing, so the size is plain arithmetic: width × height × 3, plus a 54-byte header. A blank screenshot and a busy photo of the same dimensions weigh exactly the same.
JPEG spends bits only where there is detail, so the drop is steep. The JPG column is what quality 82 usually produces; the scanner row uses 90.
| Pixels | 24-bit BMP | As JPG | Typical source |
|---|---|---|---|
| 640 × 480 | ≈ 900 KB | 50–100 KB | Old-program screenshot |
| 1024 × 768 | ≈ 2.3 MB | 120–250 KB | Legacy software export |
| 1920 × 1080 | ≈ 5.9 MB | 250–600 KB | Full HD screen capture |
| 2550 × 3300 (Letter, 300 dpi) | ≈ 24 MB | 1–2.5 MB at quality 90 | Flatbed scanner page |
Paint converts one file; this page converts the folder
Windows can already convert one file: open the bitmap in Paint, Save As, choose JPEG. It cannot do forty scans in one go, and it offers no quality control. The BMPs that land here have three usual origins, each with its own right setting.
- Paint and older Windows programs: for years the Save dialog listed 24-bit Bitmap first, and the habit stuck. Screenshots and flat-color graphics are fine at 82.
- Scanner or all-in-one printer software: many drivers list BMP and TIFF ahead of JPG or PDF. A page of text needs 90 or higher.
- Lab, medical and industrial equipment: microscopes, biometric readers and capture cards write BMP because it is the simplest format to produce. If the pixels are measurements, pick PNG instead.
Scanned text: JPG at 90, PNG for line art, or straight to PDF
JPEG's weak spot is a hard edge beside a flat area, exactly what a letter on white paper is. At 82, small print picks up a faint gray fringe; at 70 it smears. At 90 or 95 the fringe is gone and a Letter-size scan still lands around 1–2.5 MB, a tenth of the bitmap.
Pure black ink on white, no shading, is usually smaller as PNG than as JPG and stays razor sharp: switch the format before generating. If the portal wants a PDF, skip the JPG step: the JPG to PDF page accepts BMP and can put every page in one file. A needlessly color scan gets smaller still on the black and white page.
If a .bmp is refused
Your browser does the decoding and handles ordinary uncompressed 24- and 32-bit bitmaps without fuss. Rare variants may be refused: damaged files and unusual compressed BMP flavors. Same fix for all: open it in Paint, Save As PNG or 24-bit BMP, and drop the new file here.
One more limit: anything over 10,000 px on its longest side is scaled down to 10,000 before encoding. The JPG carries no metadata either: BMP has no EXIF, and this page strips it regardless.
Frequently asked questions
How much smaller will my BMP be as a JPG?
Photos and screenshots typically come out 10 to 20 times smaller at the default quality of 82: a 5.9 MB 1920 × 1080 bitmap becomes roughly 250–600 KB. A scanned text page at quality 90 shrinks about tenfold, because sharp edges cost more bits.
Does converting BMP to JPG lose quality?
JPEG is lossy, so technically yes, but at 82 or above the difference is invisible on a photo or a screen capture, even in Compare. Text and line art show it first; use 90 or higher for those, or PNG if the image must stay pixel-exact.
Paint already saves as JPEG. Why use this page?
Paint handles one file per Save As and gives you no quality setting. Here you drop the whole folder, choose the quality once, see the before and after size on every card, and download everything as a single .zip.
Can I convert a whole folder of BMP files at once?
Yes. Open the folder and select all the files inside it (the folder itself cannot be dropped). There is no file count limit; on a phone with 20 MB+ scans, run batches of 10 to 20 so memory holds up.
Can't I just rename .bmp to .jpg?
No. The extension is only a label; the bytes inside are still an uncompressed bitmap. Some viewers open it anyway, but it is exactly as large as before, and any upload form that checks the real file type will reject it.
Does a BMP have transparency that gets lost?
Almost never. A standard 24-bit BMP has no alpha channel, so there is nothing to lose. The rare 32-bit variant can carry one, and if it does, those pixels become white in the JPG, the same rule that applies to PNG.
Are my scanned documents uploaded anywhere during conversion?
No. The bitmap is decoded and re-encoded by your browser on your own device; nothing leaves your machine. That is also why a 30 MB scan finishes as fast as your computer allows rather than as fast as your connection does.
My BMP is over 10,000 pixels wide. What happens?
The longest side is scaled down to 10,000 px before encoding, keeping the aspect ratio. A Letter page at 600 dpi (5100 × 6600) is well under the limit; a large-format drawing or a stitched panorama scanned at 600 dpi can exceed it and will be reduced proportionally.