Nobody picks BMP by choice. It is usually demanded by software you cannot replace: CNC control software, a laser engraver editor, an embroidery machine program, an old business application, or the firmware of an industrial display. You have a drawing, logo, or layout in PDF, and the machine only understands BMP. Taking screenshots and re-saving them in Paint is slow and imprecise.
The short answer: upload the PDF to our online PDF to BMP converter and each page becomes a separate 24-bit BMP at 150 dpi. With several pages you can download them one by one or as a ZIP archive. Free, no registration, no watermarks. Below we explain the format, file sizes, alternatives, and how to prepare images for specialized hardware.
Quick answer: PDF to BMP in 3 steps
- Open PDF to BMP and upload one PDF up to 100 MB.
- Click Convert to BMP — processing runs on our server in the background.
- Download the BMP images individually or as one ZIP archive.
What BMP is
BMP (bitmap, also DIB — Device Independent Bitmap) was introduced by Microsoft and IBM in the late 1980s for Windows and OS/2. A BMP file is a small header followed by the color of every pixel, row by row — no clever compression, no metadata. That simplicity made it the lowest common denominator: reading BMP needs no decoding library, which is why it survives in CNC and engraving tools, embroidery software, microcontrollers with small displays, old Windows business apps, and Paint. BMP supports 1, 4, 8, 16, 24, and 32 bits per pixel and theoretically RLE compression, but in practice it is almost always uncompressed.
BMP vs PDF, PNG, and JPG
| Feature | BMP | PNG | JPG | |
|---|---|---|---|---|
| Content | Text, vector, raster | Raster | Raster | Raster |
| Compression | Varies | Usually none | Lossless | Lossy |
| A4 page at 150 dpi | Tens to hundreds of KB | About 6 MB | Usually hundreds of KB | Usually hundreds of KB |
| Quality | Original | Lossless | Lossless | Possible artifacts |
| Legacy compatibility | Low | Maximum | High | High |
If your software accepts PNG, use PDF to PNG — same lossless quality at a fraction of the size. For photos and previews, PDF to JPG works. Choose BMP only when there is no other option.
Step-by-step: converting PDF to BMP online
- Prepare the document. No password, under 100 MB. If you need one drawing from a big album, extract that page first.
- Open the converter. Go to PDF to BMP. No installation or sign-up.
- Upload the file. Drag the PDF onto the upload area or click to choose it. One PDF per task.
- Start the conversion. Click Convert to BMP. The task is queued on the server; keep the tab open until links appear.
- Download. Each page gets its own BMP link, and with multiple pages a ZIP archive is offered too.
- Check. Open the files in Paint or your machine software. They are numbered in page order.
Resolution, color depth, and file size
What dpi means
Dpi is the number of pixels per inch of the page when rasterizing. Our converter uses a fixed 150 dpi, giving about 1240 × 1754 pixels for an A4 page — enough for screens, documents, and most hardware tasks. It cannot be changed in the interface.
24-bit color and size
Each pixel takes three bytes (red, green, blue), giving about 16.7 million colors. Uncompressed size is width × height × 3: 1240 × 1754 × 3 ≈ 6.5 million bytes, so roughly 6 MB per A4 page regardless of content. A 50-page document produces around 300 MB of images. BMP compresses very well in ZIP, so the archive is usually much smaller than the sum of the files.
Keep this in mind when planning: if you only need a cover page or a single drawing, extract it before converting rather than downloading hundreds of megabytes. And if you are sending BMP files by e-mail or messenger, send the ZIP archive — it transfers faster and keeps pages in the correct order, which matters when the receiving software imports files by name.
Need monochrome or a specific size?
Machine software sometimes wants a 1-bit BMP or exact pixel dimensions. Re-save the BMP in IrfanView (Decrease Color Depth, Resize) or GIMP (Image → Mode → Indexed with a two-color palette).
BMP variants and why they matter
The .bmp extension covers several variants, and they are the main source of compatibility problems:
| Color depth | Colors | Typical use |
|---|---|---|
| 1-bit | 2 (black and white) | Engraving, simple displays, stencils |
| 4-bit | 16, palette | Very old software, icons |
| 8-bit | 256, palette or grayscale | Embroidery, embedded devices |
| 24-bit | About 16.7 million | Universal: Paint and most programs |
| 32-bit | 16.7 million plus alpha | Graphics with transparency, not supported everywhere |
Our converter produces 24-bit BMP, the most compatible variant. Reducing color depth later is easy, while going the other way cannot restore lost colors — so starting from full color is the right strategy.
Tips for CNC, engraving, and embroidery
- Crop margins — engraving software treats white margins as part of the image.
- Use high-contrast sources — thin gray lines may vanish when converted to monochrome.
- Consider vectors — for contour cutting, DXF or SVG is better; BMP shines for raster engraving and embroidery digitizing.
- Check scale — 150 dpi is about 59 pixels per centimeter; verify physical size if your software reads dpi from the file.
Alternative ways to convert PDF to BMP
Photoshop and GIMP
Both open a PDF page at a chosen resolution and save it as BMP. Pros: full control, GIMP is free. Cons: page-by-page manual work; Photoshop is paid.
IrfanView and XnView
With the Ghostscript plugin they open PDFs and batch-save pages as BMP while changing color depth and size. Pros: fast batch processing. Cons: extra components to install.
Ghostscript and ImageMagick
Ghostscript, the engine behind our service, outputs BMP directly:
gs -dNOPAUSE -dBATCH -sDEVICE=bmp16m -r150 -sOutputFile=page-%03d.bmp document.pdf
Use the bmpmono device for monochrome. With ImageMagick:
magick -density 150 document.pdf -type TrueColor page-%03d.bmp
Screenshot and Paint
Works for one page, but resolution is limited by your screen and fine details are lost.
Common problems and fixes
Password-protected PDF
If you know the password and may use the document, run Unlock PDF first.
Damaged file
Try Repair PDF and convert again.
PDF too large or too many BMPs
Compress or split the PDF to fit 100 MB. Output size depends on page count, about 6 MB per A4 page.
Blurry image
150 dpi is fine on screen, but fine drawing details may look soft when zoomed. Use Ghostscript with -r300 for more detail. A low-quality scan will not get sharper.
Colors look different
Print PDFs may use CMYK while BMP is RGB, so slight shifts are normal.
Machine software rejects the file
It may require a specific color depth or pixel size — re-save in IrfanView or GIMP.
Security and privacy
No registration, files processed on our server in a background queue, results downloaded by link, and everything deleted automatically within 48 hours. Nothing is published or shared.
FAQ
Is PDF to BMP free?
Yes — free, no registration, no watermarks.
How many BMP files will I get?
One per page, plus a ZIP archive when there are several pages.
Why is each BMP about 6 MB?
BMP stores every pixel uncompressed: 1240 × 1754 × 3 bytes for A4 at 150 dpi.
Can I choose resolution or monochrome?
No, output is fixed at 150 dpi, 24-bit. Adjust in an image editor afterwards.
Is BMP better than PNG?
Not in quality — both are lossless. BMP only wins on legacy compatibility.
How do I turn BMP back into a PDF?
Re-save the BMP as PNG or JPG in any editor, then use PNG to PDF or JPG to PDF. The result will be an image-only PDF without a text layer.
Can I convert several PDFs at once?
One PDF per task. Merge PDFs first if needed.
Conclusion
BMP is heavy but universally compatible, and still essential for CNC, embroidery, embedded devices, and legacy software. Skip the screenshots: upload your document to our PDF to BMP converter and download every page or the whole ZIP — free, no registration, no watermarks.