1Upload the BMP images that came out the wrong way round.
2Pick a turn of 90, 180 or 270 degrees.
3Apply the rotation; the pixels and the orientation flag are reconciled so every viewer agrees on which way is up.
4Download the rotated BMP file.
Rotate BMP FAQ
Does the format decide whether rotation is lossless?
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It does. 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 property is exactly what determines whether a quarter turn is free or costs a re-encode.
Anything specific to BMP I should know?
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Yes — because nothing is compressed, a BMP is fast to read and edit but punishing to upload, and it carries no metadata to preserve. It is the kind of thing that explains why a file looks right in one application and wrong in another.
Can I rotate a whole batch in one go?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Can I run Rotate BMP on several BMP images at once?
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Yes — upload the set and they process in parallel under one set of settings. Lossless files are larger, so a big batch is bound by your upload speed rather than by the processing itself.
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 Rotate BMP cost anything?
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No. Rotate BMP is free without an account and adds no watermark. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
Is there a file size limit on Rotate BMP?
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Yes: free accounts process images up to 5 MB each; lossless sources hit that ceiling sooner than photographs do, because nothing has been thrown away yet. If you are over it, converting to PNG first is often enough on its own — a BMP is routinely ten to twenty times the size of the identical image as PNG.
Why does a PNG site host Rotate BMP?
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PNG.to is built around the format you use when you cannot afford to lose a pixel: lossless, alpha-capable, and the correct answer for screenshots, logos, line art and anything with hard edges. Image work is rarely one step: people arrive to change a format and leave needing the picture a different size, a different weight or a different shape. Running Rotate BMP on the same upload pipeline, the same size caps and the same account is the whole reason it is here rather than on a fourth tab.
What should I do with the result once Rotate BMP is finished?
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The converter on this site moves images to and from PNG, JPG, WebP, GIF and SVG — which is the step where the decision about transparency actually gets made. That is the step most people actually came for, and doing it after Rotate BMP rather than before it means the conversion works from the file you finally settled on.
Is Rotate BMP here the same tool the sibling sites run?
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The engines are shared — the same libraries, the same workers, the same limits. What differs is the advice, and the advice here starts from one fact about the format this site is named after: there is no quality slider to get wrong — a PNG round-trips bit-exactly, so the only thing edits cost you is file size. A PNG site is opinionated about where PNG is the right destination and where it is not, and that judgement is worth more than the button.
Do I need an account, and does anything get kept?
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No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
