Why is the PDF so much smaller than the BMPs?

BMP has no compression at all. The PDF stores each image compressed, which for photos and screenshots is 10–20× smaller with no visible change.

Are 1-bit and 8-bit BMPs supported?

Yes — monochrome, palette and 24/32-bit bitmaps all decode.

Can I keep the images lossless?

For diagrams with flat colours, convert BMP to PNG first and use PNG to PDF, which embeds losslessly.

Is anything uploaded?

No, the conversion runs on your device.

PDF Tools

BMP to PDF

BMP files from Paint, old scanners and industrial software are huge and hard to share. As a PDF the same images are a fraction of the size and open on any device.

Runs in your browser — files never leave your device.

Drop BMP files here

or click to browse · paste from clipboard · up to 100 MB each

Select files

Options

Page size

Orientation

Margin

Why convert BMP to PDF

BMP stores every pixel uncompressed — a full-screen screenshot is 6 MB, a scanned A4 page 25 MB. Packing them into a PDF compresses each page and puts them in a format that email, phones and document systems all accept.

The bitmaps are decoded in your browser and embedded as JPEG (photos and screenshots) so the resulting PDF is typically 10–20 times smaller than the BMPs while looking identical on screen and in print.

How to convert BMP to PDF

Drop the BMP files onto the page.
Choose page size and orientation.
Click Convert and download the PDF.

About the formats

BMP · Windows bitmap · .bmp

An uncompressed Windows image format from the 1990s: simple and lossless, but files are enormous.

A 12-megapixel BMP is about 36 MB; the same photo as JPG is 2–4 MB.
BMP usually has no transparency and no metadata such as camera settings.
Still produced by some scanners, screenshot tools and legacy software.

PDF · Portable Document Format · .pdf

The fixed-layout document standard: looks the same on every device and printer, which is why forms, invoices, contracts and reports are shared as PDF.

A PDF can contain vector text, embedded fonts, images, form fields, annotations and digital signatures.
Scanned PDFs are just pictures of pages; they need OCR before the text can be searched or copied.
PDF is an open ISO standard (ISO 32000) since 2008.