Convert BMP to PNG Online
Shrink uncompressed BMP bitmaps into compact PNG files without losing a single pixel. Both formats are lossless, but PNG compresses the same image into a fraction of the space.
How to Convert BMP to PNG in Three Steps
Upload one BMP or a batch of files, select PNG as the output format, then download your compressed images as a ZIP.
Step 1
Add Your BMP
Drop a BMP file into the converter or choose several at once.
Step 2
Choose PNG
Select PNG output to compress the bitmap without discarding image data.
Step 3
Download PNG
Save each file separately or export the whole batch in one ZIP.
Why Convert BMP to PNG — Lossless Compression That Shrinks Files Dramatically
BMP is the original Windows bitmap format and it is about as simple as an image format gets: pixels are stored essentially raw, with little or no compression applied. That simplicity made sense in 1990, but it means a perfectly ordinary photograph can weigh tens of megabytes, and a folder full of legacy bitmaps can consume gigabytes for no benefit whatsoever. Because nothing is compressed, the size buys you absolutely nothing in return: no extra colour, no extra detail, no extra fidelity.
PNG applies lossless DEFLATE compression to exactly the same pixel data. Nothing is discarded, nothing is approximated, and no quality slider is involved, because the two formats describe the same image. The only difference is how efficiently that description is stored. In practice a BMP shrinks by somewhere between five and twenty times, depending heavily on content: flat-color graphics, screenshots and diagrams compress spectacularly well, while noisy photographic detail compresses far less. Either way the saving is real and immediate, and it comes without touching a single pixel of image data.
The conversion runs entirely in your browser. Your BMP is decoded by the browser’s imaging engine, drawn onto a canvas, and re-encoded as a PNG on your own machine. Alpha data present in the source bitmap is carried through into the output. Because both formats are lossless, the result is visually identical to the original, just dramatically smaller and far easier to move around. You can verify this yourself by opening both files side by side, because there is genuinely no visual difference to find.
Where this matters in practice is usually inherited data. Companies hold archives of bitmaps exported by old software. Scanners and legacy line-of-business applications still write BMP by default. Email attachments bounce because the file is too large. Upload forms reject it because it exceeds a size cap. Designers need those assets on the web, where an uncompressed bitmap is simply indefensible. Archivists inherit folders of them from decommissioned systems and need them readable without keeping obsolete software alive.
Converting solves all of it without asking you to install an image editor or trust a file to an unknown server. Everything is processed locally, so confidential scans and internal documents stay on your device. There is no sign-up, no conversion quota, no limit on how many files you can run through, and no watermark on any PNG you download. A whole folder of bitmaps can be converted in one batch and exported as a single ZIP file.
Huge Size Savings
Lossless PNG compression typically shrinks a BMP file by five to twenty times.
Nothing Discarded
Both formats are lossless, so no pixel data is thrown away during conversion.
Transparency Preserved
Alpha data in the source bitmap is carried into the PNG output.
Batch Mode
Convert a folder of BMP files and download every PNG in one ZIP.
Runs In Browser
Decoding and encoding happen locally, so your files are never uploaded.
No Watermark
Downloaded PNGs are completely clean and unbranded, with no logo or watermark added.
FAQ
Frequently Asked Questions
BMP stores pixels with little or no compression, so files are enormous for no benefit. PNG applies lossless compression to the identical image data, typically reducing size five to twenty times while preserving every pixel, making the file practical to email, upload and archive.
Expect somewhere between five and twenty times smaller, with the result depending heavily on image content. Flat-color graphics, screenshots, diagrams and logos compress extremely well, while noisy photographic detail compresses far less because there is less repetition for the encoder to exploit.
Yes, completely. Both formats are lossless, so the PNG contains exactly the same pixels as the source bitmap. No quality setting is offered because there is nothing to trade off. The reduction in file size comes entirely from more efficient compression, not from discarding image data.
Where the source bitmap carries alpha data, it is preserved through the conversion. The image is decoded, drawn onto a canvas that retains the alpha channel, and re-encoded as a PNG that supports transparency. Nothing is flattened onto a solid background during the process.
Yes. Add as many BMP files as you need and every one is converted in the same run. Download each PNG individually or export the complete set together as a single ZIP archive, which is by far the fastest way to reclaim space in a legacy asset folder.
No. Your bitmap is read through the browser’s File API, decoded locally, drawn onto a canvas and encoded as PNG on your own device. Nothing is transmitted, nothing is stored after the tab closes, and no account is needed to use the tool.
BMP was designed for simplicity rather than efficiency. It stores pixel values as raw data with minimal compression, so a single image can occupy tens of megabytes. That was acceptable when storage was the only concern, but it makes the format impractical for email and web delivery.
Yes. There is no registration, no daily conversion limit, no file size cap beyond your device memory and no premium tier. Convert a single bitmap or an entire archive on identical terms, and every PNG you download is clean with no watermark added.
None at all. Because both formats are lossless and no quality slider applies, the PNG is pixel-for-pixel identical to the source bitmap. The only change is file size, and the only visible difference you might notice is faster uploads and more free disk space afterwards.
Choose PNG when pixel accuracy matters – screenshots, diagrams, pixel art, text, or long-term archiving – because PNG is lossless. Choose JPG only for photographs where the smallest possible file beats exact fidelity, since JPG compression is lossy.