BMP to PDF
Convert Windows BMP (bitmap) images into a single PDF document. Files are processed in your browser — they never leave your device.
BMP to PDF converts the uncompressed Windows bitmap format — first introduced with Windows 1.0 in 1985 — into a single PDF document using pdf-lib running in your browser via a Web Worker. BMP doesn't carry EXIF or other metadata; it's just pixels. The conversion re-encodes each bitmap as JPEG before embedding, which dramatically reduces the output PDF's file size compared to the uncompressed source.
What is BMP to PDF?
BMP (Bitmap, sometimes Device-Independent Bitmap or DIB) is the native image format Microsoft introduced with Windows 1.0 in <strong>1985</strong>. It stores pixels uncompressed by default — every pixel of a 1080p BMP takes 3 bytes for RGB, producing a 6 MB file for a screenshot that would compress to ~200 KB as PNG. That uncompressed nature is why BMP is mostly obsolete for everyday use; it persists in legacy industrial and embedded software, vintage Windows screenshots, and a few specialised tools that need byte-aligned pixel data.
Converting BMP to PDF is usually about reducing file size — a folder of BMP screenshots from a legacy system shrinks dramatically when re-encoded as JPEGs inside a PDF — and about making the images shareable. Email clients and messaging apps increasingly reject BMP attachments because of the size; PDF works everywhere. Most online BMP converters upload your files to a remote server. This tool runs the conversion entirely in your browser.
How does the in-browser BMP conversion work?
Pikowl loads each BMP into a Web Worker — a background thread inside your browser. The worker uses the browser's native createImageBitmap to decode BMP pixels — every modern browser supports BMP decoding natively without an extra library. The decoded bitmap is drawn onto an OffscreenCanvas, re-encoded as JPEG at quality 0.92, and embedded into a new PDF using pdf-lib. The output PDF is offered as a downloadable Blob via URL.createObjectURL. Nothing is sent to any server.
Is it safe to convert BMP files here?
Yes. Open the network tab in DevTools while you use the tool — you will see no outbound requests during the conversion. BMP files are read locally via the File API, processed in a sandboxed Web Worker, and the resulting PDF lives only in your browser's memory until you download it.
Does BMP carry hidden metadata?
No. BMP predates EXIF and was never extended to carry camera metadata, GPS coordinates, capture timestamps, or editing history. The format header records only the dimensions, colour depth, and compression flag — everything else is pixel data. That's why this tool doesn't surface an "EXIF stripped" claim: there's no EXIF to strip. The canvas re-encode does still produce a clean output (no embedded thumbnails, no unused header fields), but there's no privacy story to tell here that wouldn't be misleading.
What are the limits and why?
Up to 20 BMPs per conversion, 50 MB per file, with a soft warning at 100 MB combined and a hard cap at 150 MB. The per-file limit is double the JPG limit because uncompressed BMPs are typically 5-10× the size of equivalent JPEGs at the same dimensions. A 4K BMP is around 24 MB raw; a 6K screen capture in BMP can exceed 40 MB. The file-count limit is lower because uncompressed pixel data is heavier in memory than compressed JPEG.
How does Pikowl compare to Smallpdf and iLovePDF for BMP?
The substantive differences are processing location, daily-use limits, and pricing. Numbers below reflect the public free-tier offers from each service as of April 2026.
| Feature | Pikowl | Smallpdf | iLovePDF |
|---|---|---|---|
| Where files are processed | Your browser | Remote server | Remote server |
| Sign-up required | No | Optional | Optional |
| Output quality | Re-encoded as JPEG q=0.92 | Server-side re-encoded | Server-side re-encoded |
| Max file size (free) | 25 MB | 5 MB | 200 MB (combined) |
| Price | Free | $9/mo for unlimited | $7/mo for premium |
Sources: smallpdf.com/pricing and ilovepdf.com/pricing, retrieved April 2026.
Common Uses
- Legacy enterprise software exports: Many industrial and medical systems still output BMP; convert before sharing with modern tooling that prefers PDF.
- Vintage Windows screenshots: Print Screen on Windows historically saved BMPs; archive them as PDFs to dramatically shrink the file size.
- Embedded device captures: Some POS systems, ATMs, and industrial controllers export receipts as BMP; convert to PDF for accounting workflows.
- Pixel-perfect archival: When BMP was used because the producer needed byte-aligned pixel data, the PDF version is the portable preservation copy.
- Sending screenshots to cloud printers: Print services often want PDF; converting BMP saves an extra step.
- Software documentation: Older app screenshots saved as BMP can be bundled into a PDF user manual.
FAQ
Why are BMP files so large?
BMP stores pixels uncompressed by default — 3 bytes per pixel for 24-bit RGB, plus a small header. A 1920×1080 BMP is roughly 6 MB; a 4K BMP is around 24 MB. Other formats (JPG, PNG, WebP) apply compression to shrink this dramatically. Converting BMP to PDF — which embeds the pixels as JPEG inside the PDF — typically shrinks the file by 10× or more.
Does Windows still produce BMP files?
Rarely. The Windows Print Screen → Paint workflow defaults to PNG since Windows 7, and the Snipping Tool uses PNG. BMP persists primarily in legacy industrial software, embedded devices (point-of-sale systems, medical equipment), and a few specialised graphics tools that need byte-aligned pixel data. If you have a folder of BMPs, it's almost certainly from a legacy system.
Why convert BMP to PDF instead of PNG or JPG?
PDF is the universal sharing format — every device opens it. PNG would preserve quality losslessly but doesn't open as cleanly in email previews and document workflows. JPG would shrink the file but doesn't combine multiple images into a single shareable container. PDF gives you both portability and one-file-per-set bundling.
Does this support 32-bit BMPs (with alpha channel)?
Yes — createImageBitmap decodes 32-bit BMPs natively, but the alpha channel is flattened to white when re-encoded as JPEG (JPEG has no alpha support). If you need transparency preserved in the PDF, save the source as PNG and use our PNG to PDF tool, which uses pdf-lib's lossless embedPng path.
Will the PDF be smaller than the BMPs?
Almost always, yes — typically 10-50× smaller. BMP is uncompressed; the PDF embeds JPEG-compressed versions of the same pixels. A 50 MB folder of BMPs will usually produce a 1-5 MB PDF.
Why no "EXIF stripped" claim?
BMP doesn't carry EXIF metadata — no GPS, no capture timestamp, no device info. There's nothing to strip. Other tools in our PDF category that do strip EXIF (JPG to PDF, HEIC to PDF, PNG to PDF) carry that claim because their input formats can carry EXIF; BMP can't, so we skip the claim. Honesty matters.
Are BMP files uploaded to a server?
No. The conversion runs entirely in your browser — open DevTools' network tab and you'll see no outbound requests during the process. BMP files are read from your disk via the File API, decoded by createImageBitmap in a Web Worker, embedded into a PDF using pdf-lib, and offered back as a download.
By the Numbers
- BMP was introduced with Windows 1.0 in 1985 and remains structurally similar 40 years later — the BITMAPINFOHEADER format from Windows 3.0 is still the most common variant.
- An uncompressed 24-bit BMP requires roughly 3 bytes per pixel plus a 54-byte header, which is why a 1920×1080 BMP weighs ~6 MB and a 4K BMP weighs ~24 MB.
- Despite Windows now defaulting to PNG for Print Screen and Snipping Tool, BMP persists in legacy industrial software, embedded systems, and some medical equipment where byte-aligned uncompressed pixel data simplifies downstream processing.