PDF to BMP Converter

Convert PDF to BMP Online

BMP is the Windows Bitmap format that legacy Windows software, scientific imaging tools, industrial HMI panels and embedded displays still expect, because decoding it needs almost no code. This converter renders each page of your PDF and writes it as its own .bmp file at the DPI you choose. One correction up front, because nearly every other page on this topic gets it wrong: the files this tool produces are not 24-bit uncompressed bitmaps. Depending on which quality preset you pick you get a 16-bit uncompressed bitmap or an RLE-compressed palette bitmap — the details are below, and they matter for both file size and which software will open the result.

How to Convert PDF to BMP

1. Upload Your PDF File: Drag and drop the PDF onto the page or click "+ Add Files" to browse. Multi-page documents are accepted and rendered page by page.
2. Set Conversion Quality (Render DPI): This dropdown is the render resolution, not a compression dial. It offers 72, 96, 150, 200, 300, 400, 600 and 1200 DPI, and it drives the pixel dimensions of every page image.
3. Pick a Quality Preset: Only three entries are available for BMP — High, Medium and Low, listed in that order — and each writes a structurally different file. Read the table below before choosing; the higher-quality entries you may see on other image pages are not offered here, and neither is a target file size.
4. Set the Background Colour and Convert: Under "Image Transparency", the "Color" dropdown fills anything transparent on the page; White is selected. Click Convert and each page returns as its own BMP, individually plus a "Download All (Zip)" button. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours. No sign-up, no watermark.

What Each Quality Preset Actually Writes

The counter-intuitive one is Low. Fewer palette entries should mean a smaller file, but run-length encoding rewards long runs of identical pixels, and heavier dithering across a smaller palette breaks those runs up. We measured both presets on a 1275 × 1650 text page render: Medium produced 259,916 bytes and Low produced 262,492 bytes — Low came out marginally larger. Treat Medium as the default choice and Low as a stylistic reduction, not a compression setting.

How Big a High-Preset BMP Gets

High writes two bytes per pixel with no compression, so its size is arithmetic rather than content-dependent: page width in pixels, rounded up to a four-byte row boundary, times two, times the page height, plus a 54-byte header.

Those are per page. A 20-page document rendered at 600 DPI on the High preset is well over a gigabyte before you have downloaded anything, which is the single best argument for either dropping the DPI or switching to Medium.

Common Problems and Fixes

• "My BMP is enormous." That is the High preset, which stores two uncompressed bytes for every pixel. Drop the Conversion Quality to 150 DPI, switch to Medium, or use PDF to PNG, which is lossless and far smaller.
• "My software refuses to open the file." Medium and Low write RLE-compressed bitmaps, and minimal or embedded BMP readers frequently handle only uncompressed BI_RGB. Low additionally uses the 124-byte V5 header, which very old readers may not parse. If a specific tool is rejecting the file, try the High preset — it is the plainest structure of the three.
• "Colours look banded or speckled." High is 5-5-5 colour, so a smooth gradient has only 32 levels per channel to work with. Medium and Low quantise to a palette and dither, which trades banding for a fine speckle pattern. Neither is a bug; for smooth tones on a page render, PDF to PNG preserves full colour.
• "I got 30 files instead of one." Expected. Every PDF-to-image conversion here writes one image per page. Use the "Download All (Zip)" button to take them in one go.
• "There is no option to set a target file size." Correct — the target-size control is not offered for BMP output, so the DPI and the quality preset are the only two levers on file size.

Frequently Asked Questions

Is the BMP this tool produces uncompressed 24-bit?

No, and this is the most widespread misconception about PDF-to-BMP converters. The High preset writes an uncompressed bitmap, but at 16 bits per pixel in 5-5-5 layout — 32,768 possible colours, not 16.7 million. Medium and Low write 8-bit palette bitmaps that are run-length compressed. If you need genuine 24-bit truecolour with no quantisation, PDF to PNG is the target that gives it to you.

Which preset should I pick for a document page?

Medium, in almost every case. A text page is mostly flat white with black glyphs, which is exactly the content run-length encoding handles well, and a 256-colour dithered palette is more than enough for text and line art. Choose High only when a downstream tool insists on an uncompressed bitmap, and treat Low as a look rather than a size saving.

Why is the Low preset producing a bigger file than Medium?

Because both use run-length encoding, and RLE compresses runs of identical pixels. Low quantises to 86 colours and dithers to compensate, and that dithering scatters the image with alternating pixels that break long runs apart. Medium has a larger palette, plus a light smoothing pass before quantisation, so its runs stay longer. We measured Medium at 259,916 bytes against Low at 262,492 bytes on the same 1275 × 1650 page render.

Will the text in my PDF stay selectable?

No. Rasterising a page converts its text into pixels, so nothing can be selected, searched, copied or clicked afterwards, and links, bookmarks and form fields are gone. If the text has to stay live, keep the document as a PDF; if you only wanted it smaller, compress the PDF instead of converting it to images.

Does the BMP keep transparency from my PDF?

No. BMP has no dependable alpha support across common readers, and the alpha-preserving "Unchanged" entry under Image Transparency is not offered for this target. Every page is composited onto the colour in that dropdown — White unless you change it. Use PDF to PNG when transparent regions need to survive.

What DPI should I choose?

Match it to the end use, and remember DPI multiplies pixel count rather than trading quality against artefacts. 72-96 DPI is fine for thumbnails, 150 DPI is comfortable for on-screen reading, 300 DPI is the print-grade standard, and 600 DPI is for OCR of small type or archival capture. On BMP specifically, each step up is expensive — the High preset roughly quadruples in size when you double the DPI.

Is "Conversion Quality" the same as the Quality Preset?

No, and the two labels sitting near each other confuses people. "Conversion Quality" is the render DPI, which decides how many pixels each page is drawn at. "Quality Preset" is the BMP encoding choice — 16-bit uncompressed versus 8-bit palette with RLE. They are independent: you can render at 600 DPI and still write a Medium palette bitmap, or render at 96 DPI and still write High.

Is converting a PDF to BMP on xconvert private?

Your PDF is uploaded over an encrypted connection, rendered on our servers, and deleted automatically after a few hours — never shared, never made public. There is no sign-up and no watermark. With BMP the practical constraint is almost always the download rather than the upload, since a single High-preset page at 300 DPI is already around 17 MB and every page produces one.