BMP To PDF
Convert BMP images to PDF in seconds. Upload one or multiple bitmap (BMP) files, arrange the order, and download a clean PDF for printing, archiving, or sharing. Perfect for legacy images and scanned pages. Fast, secure, and free to use with no registration required.
BMP to PDF Converter
The BMP to PDF Converter turns bitmap (BMP) image files into PDF documents. Upload one or multiple BMP files, set the page size, orientation, margin, and whether to combine all images into one PDF — then click Convert to PDF and download the result. The conversion runs in the browser with no software installation.
BMP (Bitmap) is one of the oldest digital image formats, developed by Microsoft for Windows. It stores image data as raw, uncompressed pixel values — producing files that are much larger than modern formats like PNG or JPG for the same image. BMP files are most commonly encountered from older scanners, legacy software, Windows Paint exports, and archival systems that pre-date more efficient image formats. Converting BMP to PDF makes these files portable, printable, and easy to share without requiring any image viewing software on the recipient's side.
How to use the BMP to PDF Converter
- Click Select a File or drag and drop your BMP files into the upload area. Guest users can upload up to 5 images (10 MB each); registered users up to 20 images (40 MB each). Note that BMP files are very large — a single A4-sized scan at 300 DPI can be 20–25 MB. If files exceed the upload limit, see the file size section below.
- Configure the page size, orientation, and margin. The settings reference table below explains every option and when to use it.
- Choose whether to merge all images into one PDF or generate a separate PDF per image. For multi-page scanned documents where each page was saved as a separate BMP, enable Merge to produce one combined document.
- Set the page order if converting multiple images. The output follows the sequence shown. Rename BMP files with numeric prefixes (01-, 02-, 03-) before uploading to control order via alphabetical sort.
- Click Convert to PDF. Download and preview the result — check image clarity, page order, and file size — before sharing or submitting.
Why BMP files are so large — and what to do about it
BMP stores every pixel of an image as raw color values with no compression algorithm applied. A 24-bit color BMP file stores three bytes (red, green, blue) for every single pixel in the image. The result is that file size scales linearly with pixel count: double the resolution, double the file size. There are no tricks, no algorithms, and no quality trade-offs — just raw data.
To put this in concrete terms, a scanned A4 page at 300 DPI (the standard for clear text) produces an image approximately 2,480 × 3,508 pixels. At 24 bits per pixel, this is approximately 25 MB per page. A 10-page document scanned to BMP is approximately 250 MB of raw image data. Modern formats reduce this dramatically:
| Image dimensions | BMP (24-bit, uncompressed) | PNG (lossless) | JPG (high quality) | Size reduction vs BMP |
| 800 × 600 px (small scan) | ~1.4 MB | ~200–400 KB | ~100–200 KB | PNG: ~70–85% smaller. JPG: ~85–93% smaller. |
| 1,024 × 768 px (standard scan) | ~2.4 MB | ~400–700 KB | ~150–350 KB | PNG: ~71–83% smaller. JPG: ~85–94% smaller. |
| 1,920 × 1,080 px (Full HD) | ~6.2 MB | ~800 KB–2 MB | ~300–700 KB | PNG: ~68–87% smaller. JPG: ~89–95% smaller. |
| 2,480 × 3,508 px (A4 at 300 DPI) | ~25 MB | ~3–8 MB | ~1–3 MB | PNG: ~68–88% smaller. JPG: ~88–96% smaller. |
| 3,508 × 4,961 px (A3 at 300 DPI) | ~50 MB | ~6–15 MB | ~2–6 MB | PNG: ~70–88% smaller. JPG: ~88–96% smaller. |
The 10 MB per file upload limit for guest users may be hit by a single high-resolution BMP scan. A scanned A4 page at 300 DPI is approximately 25 MB as a BMP. If your BMP files exceed the upload limit, the most practical solution is to convert them to PNG first — using Windows Paint (Save As → PNG) or any image editor — then upload the PNG versions, which will be 70–88% smaller while maintaining identical image quality. The PDF output from a PNG source is visually identical to a PDF from the equivalent BMP source, because PNG is also lossless.
BMP vs PNG vs JPG — choosing the right source format
If you have a choice of format for your images, the table below helps you decide which produces the best PDF output:
| BMP | PNG | JPG | |
| Compression | None or minimal (RLE). Every pixel stored at full bit depth. File sizes are very large. | Lossless. Every pixel preserved exactly. Efficient for flat-color areas. Moderate file size. | Lossy. Discards some data to achieve small file sizes. Best for photographs. |
| Image quality | Perfect — no compression artefacts, no quality loss. Every pixel is exactly as captured. | Perfect — lossless compression, no quality loss of any kind. | Excellent for photos; introduces artefacts on text and sharp edges at higher compression. |
| Transparency | None. BMP does not support transparent pixels. All areas have a solid color. | Full alpha channel. Any pixel can be any opacity from fully transparent to fully opaque. | None. Transparent areas become white or filled with a background color when saved as JPG. |
| File size | Very large. A Full HD (1920×1080) 24-bit BMP is approximately 6 MB. An A4 page at 300 DPI is approximately 25 MB. | Moderate. Typically 70–88% smaller than equivalent BMP for most image types. | Small. Typically 88–96% smaller than equivalent BMP for photographs. |
| Practical use | Legacy systems, some scanner output, Windows Paint default. Not practical for sharing or email due to file size. | Screenshots, diagrams, icons, web graphics, any image requiring lossless quality. | Photographs, camera images, scanned photo documents. |
| When to convert to PDF from | When BMP is the only available format. If PNG or JPG versions exist, use those for smaller, more efficient PDF output. | Preferred for screenshots, UI images, and text-heavy scans — produces sharp, well-sized PDF pages. | Preferred for photographs — small file size with excellent color reproduction. |
If BMP is the only available format, use it directly — the PDF output will have the same image quality as any other lossless format, because BMP stores pixel data with no compression. The disadvantage is only file size: the BMP is large to upload and the resulting PDF will embed a large image. Use the PDF Compressor after conversion to reduce the output file size significantly. If you regularly work with BMP files and need smaller outputs, converting BMPs to PNG using any image editor (Windows Paint, GIMP, Photoshop, macOS Preview) before processing them produces identical quality at a fraction of the file size.
Conversion settings — what each option does
| Setting | Option | When to use it |
| Page Size | ||
| Page Size | Fit (same page size as image) | The PDF page matches the exact pixel dimensions of the BMP file. No scaling is applied. Use when the BMP was created at a known resolution and the exact dimensions must be preserved — technical drawings, diagrams, or images captured at a precisely specified pixel size. |
| Page Size | A4 (297 × 210 mm) | The BMP image is scaled to fill a standard A4 page. Use for documents intended for printing in Europe, Asia, Australia, and internationally. BMP files from flatbed scanners set to A4 page size will fit A4 pages exactly at the appropriate DPI. |
| Page Size | US Letter (215.9 × 279.4 mm) | The BMP image is scaled to fill a US Letter page. Use for documents intended for printing or distribution in the United States, Canada, or Mexico, or submission to US institutions. |
| Page Orientation | ||
| Orientation | Automatic | Detects each BMP's aspect ratio and applies portrait (taller than wide) or landscape (wider than tall) automatically. Recommended for most use cases, especially mixed batches of BMP files from different scan sessions. |
| Orientation | Portrait | Forces all pages to portrait orientation. Standard for scanned A4 documents, letter-format pages, and vertically oriented images. |
| Orientation | Landscape | Forces all pages to landscape orientation. Use for wide-format BMP files — horizontally scanned pages, wide diagrams, or landscape-format documents. |
| Margin | ||
| Margin | No Margin | The image fills the entire page edge to edge. Use when the BMP already contains its own internal margins (scanned pages typically have white borders), or when the full image must be displayed without cropping. |
| Margin | Small Margin | A narrow white border (approximately 0.5 inch / 12 mm) is added around the image. Use for documents that will be printed and handled. Adds a natural holding area and improves readability. |
| Margin | Big Margin | A wide white border (approximately 1 inch / 25 mm) is added. Use for formal submissions, professional document packs, and any context where standard document margins are expected. |
| Merge into single PDF | ||
| Merge | Enabled (checked) | All uploaded BMP images are combined into one PDF, one image per page, in the order you set. Download is a single file. Use this for multi-page scanned documents where each page was saved as a separate BMP file — this is the most common BMP use case. |
| Merge | Disabled (unchecked) | Each BMP is converted to its own independent single-page PDF. Use when each BMP is a separate, independent document rather than a page of a larger document. |
Common use cases and recommended settings
| Scenario | Recommended settings | Notes |
| Multi-page scanned document (BMP per page) | Page size: A4 or US Letter. Orientation: Portrait. Margin: Small. Merge: Enabled. | The most common BMP to PDF scenario. Scanners that export BMP produce one large file per page. Small margin ensures scanned content sits cleanly on the page. Merge is essential — the pages belong in one document. |
| Legacy archive images from old systems | Page size: Fit. Orientation: Automatic. Margin: No Margin or Small. Merge: Enabled or Disabled. | Fit preserves the original pixel dimensions for archival accuracy. If the BMP files are very large, be prepared for a large PDF output. Consider converting to PNG first if long-term storage efficiency matters. |
| Windows Paint or application screenshot (BMP) | Page size: Fit. Orientation: Automatic. Margin: Small. Merge: Depends on number of screenshots. | Windows applications, particularly older ones, sometimes default to saving screenshots as BMP. Fit preserves the screen dimensions exactly. For a single screenshot, Merge setting is not relevant. |
| Technical drawing or diagram saved as BMP | Page size: Fit or A4. Orientation: Automatic. Margin: Big. Merge: Disabled (if individual diagrams). | Big margin frames technical drawings professionally. Fit preserves exact proportions if the drawing was produced at specific dimensions. Consider converting to PNG first if image clarity at small sizes matters — BMP will produce an equally large but not better PDF than PNG. |
| Batch processing legacy document scans | Page size: A4 or US Letter. Orientation: Portrait. Margin: Small. Merge: Enabled. | Number BMP filenames numerically before uploading to maintain correct document page order. For large batches exceeding the upload limit, merge in groups and then use the Merge PDF tool to combine the group PDFs. |
Usage limits
| Account type | Daily conversions | Max file size | Images per session |
| Guest | 25 per day | 10 MB per file | Up to 5 images |
| Registered | 100 per day | 40 MB per file | Up to 20 images |
Related tools
- PNG to PDF — convert PNG images to PDF. PNG is the recommended intermediate format if your BMP files are too large to upload directly — identical quality, dramatically smaller file size.
- JPG to PDF — convert JPEG photographs to PDF. Preferred for photographic BMP content where file size is critical.
- Image to PDF — convert PNG, JPG, GIF, BMP, TIFF, and other formats in one tool. Use for mixed-format batches.
- Merge PDF — combine the converted BMP PDF with other PDF documents, or combine group PDFs after batch processing.
- PDF Compressor — reduce the file size of a large PDF produced from BMP files. Particularly important for BMP-sourced PDFs which are often very large.
- Organize PDF — reorder or remove pages in the converted PDF after generation.
Frequently asked questions
What is a BMP file?
BMP (Bitmap) is an image format developed by Microsoft for the Windows operating system. It stores image data as raw pixel values — typically 24 bits per pixel for full color — with little or no compression. BMP files are produced by older scanners, legacy Windows applications, and Windows Paint, which historically used BMP as its default save format. The defining characteristic of BMP is its very large file size: a single A4-sized page scanned at 300 DPI produces a BMP file of approximately 25 MB. Modern formats like PNG and JPG achieve equivalent or better image quality at 70–96% smaller file sizes.
Why are BMP files so much larger than PNG or JPG?
BMP stores every pixel as raw color data with no compression applied. Three bytes (red, green, blue) are stored for every single pixel in the image — the file size is simply pixels × 3 bytes, with no reduction. PNG uses lossless compression to identify and remove redundant patterns, reducing typical BMP files by 70–88% without losing any quality. JPG uses lossy compression to achieve even smaller sizes by discarding some image data. Because BMP applies no algorithm at all, it is functionally the ceiling of file size for a given image — everything else is an improvement over BMP in terms of storage efficiency.
My BMP file is too large to upload. What can I do?
The guest upload limit is 10 MB per file. A single A4-page BMP scan at 300 DPI is approximately 25 MB — well above this limit. The most practical solution: open the BMP in Windows Paint (File → Save As → PNG), macOS Preview (File → Export → PNG), or any image editor, and save it as a PNG. PNG is lossless — the image quality is identical to the BMP — but the file will be 70–88% smaller, making it practical to upload. Alternatively, register a free ToolsPiNG account to access the 40 MB per file limit, which accommodates most high-resolution BMP scans.
Does converting BMP to PDF change the image quality?
No. BMP stores every pixel with full precision — there is no quality to lose. The PDF conversion embeds the image data directly into the PDF without re-compressing or altering the pixels. The PDF output will look identical to the original BMP. The only change is that the image is now wrapped in a PDF container, making it printable and shareable through standard document workflows. File size of the PDF may be slightly smaller than the raw BMP due to PDF's internal compression of embedded images, but visually nothing changes.
Can I convert multiple BMP files into one PDF?
Yes. Upload multiple BMP files, arrange them in the correct order (or prefix filenames with numbers: 01-, 02-, 03-), and enable the 'Merge all images in one PDF' option before clicking Convert. The tool produces a single PDF with each BMP on its own page. This is the standard workflow for multi-page documents scanned to individual BMP files per page — a common output format for older flatbed scanners.
Should I convert BMP to PNG before converting to PDF?
If your BMP files are within the upload limits, you can convert directly from BMP to PDF without any intermediate step — the quality will be identical. Converting to PNG first is only necessary when BMP files exceed the 10 MB guest upload limit (most high-resolution scans do), or when you want to reduce the resulting PDF file size before converting. PNG from a BMP source is lossless, visually identical, and 70–88% smaller — making uploads faster and the resulting PDF more manageable. If file size is not a concern and files are within limits, direct BMP to PDF conversion is perfectly fine.
Why is my converted PDF file very large?
BMP files contain a large amount of raw pixel data, and this data is embedded into the PDF output. A 25 MB BMP will produce a PDF of similar size (the PDF container adds minimal overhead, and PDF may compress the embedded image slightly). For very large PDFs, use the ToolsPiNG PDF Compressor after conversion — it re-encodes the embedded images with more efficient compression, typically reducing PDF file size by 40–70% without significant visible quality loss. Alternatively, convert your BMP files to PNG first (lossless, 70–88% smaller), then use PNG to PDF for a smaller starting point.
Is the BMP to PDF Converter free?
Yes. The converter is free within the daily usage limits shown above. Guest users can run 25 conversion sessions per day and upload up to 5 images per session (10 MB each) without an account. Registering a free ToolsPiNG account increases the daily limit to 100 sessions, the file size limit to 40 MB per image — which covers most high-resolution BMP scans — and the per-session image count to 20.