1Drop your BMP images into the box above, or pick them from your device — there is nothing to install and no account to create.
2Choose how hard to squeeze: a quality or bitrate target, and optionally smaller dimensions if size matters more to you than detail.
3Start the job and let the workers re-pack the file; your original is never modified in place.
4Compare the new size against the original, then download the compressed BMP file.
Compress BMP FAQ
How much smaller will my file get?
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That is decided by the content, not by the tool. Photographic detail and film grain resist compression; flat colour, text and silence collapse. A realistic expectation is a large reduction on anything with big uniform regions and a modest one on a busy photograph or a high-motion clip.
Does the format of my file change how much I can save?
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Very much so. BMP is essentially raw uncompressed RGB rows with a small header, so it is perfectly lossless and enormous — often 10-20x the size of the same image as PNG. That determines both the headroom available and whether the saving costs you anything in fidelity.
What is the most common mistake when compressing BMP images?
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Compressing the same file repeatedly. Each pass on a lossy format is a fresh generation of loss and the savings shrink while the damage accumulates. Go from the original to your target in one step, and keep the original.
What do I get back, and can I control the trade-off?
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A single compressed file per input, at a quality or bitrate level you choose rather than a fixed default. If the result is not small enough, changing the dimensions or the duration will do more than pushing the quality slider further down.
Will Compress BMP lower the quality of my BMP images?
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No. A lossless source round-trips bit-exactly, so unless you explicitly ask for a lossy output format the pixels that come back are the pixels that went in. That is the whole reason to keep working in this family while you are still editing.
Does the alpha channel survive?
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Yes. PNG and TIFF carry a full 8-bit alpha channel and it is preserved end to end. It is only flattened if you deliberately target a format that has no alpha, in which case transparent pixels are composited onto white.
Does Compress BMP cost anything?
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No. Compress BMP runs free without an account and adds no watermark. Files are removed from the workers shortly after you download, and nothing about the image is retained.
What can I upload to Compress BMP?
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PNG, BMP and TIFF are the lossless raster formats this handles directly, and lossy sources (JPG, WebP, GIF) work too if you want them in the same batch. Multi-page TIFFs are detected and handled page by page.
Why does a PDF site host Compress BMP?
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PDF.to exists because PDF is where documents go to be shared and the worst place to keep them while they are still being worked on, so nearly every job here is about getting something into or out of that state deliberately. A document rarely arrives in the state it needs to leave in: it is too big, in the wrong order, locked, or a scan with no text in it. Compress BMP sits on the same upload and the same account as the conversions because those jobs turn up together.
What should I do with the result once Compress BMP is finished?
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The converter on this site moves documents between PDF, Word, images, plain text and eBook formats in either direction, so whatever comes out of a tool here has somewhere to go next without a second upload. Running that after Compress BMP rather than before keeps the document structure intact through the step that is most likely to flatten it.
Is Compress BMP here the same tool the sibling sites run?
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The engines are shared — the same document toolchain, the same workers, the same limits. What a PDF site adds is a view on when a file should stay a document and when it genuinely wants to become something else, which is the decision most tools quietly make for you. It also starts from one fact about the format this site is named after: a PDF is an object graph, not a page image, so text stays selectable and vectors stay sharp no matter what happens to the raster content inside it.
Do I need an account, and does anything get kept?
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No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is read and nothing is indexed. Free accounts exist for history and batch size, not for access.
