How to convert PNG to BMP without uploading it
Every "free" online PNG converter you've used uploads your images to a company server, converts them there, and — in several documented cases — keeps a copy or a live download link for days. For screenshots, logos and anything you wouldn't post publicly, that's an unnecessary risk. The safer approach is to convert the file where it already is: on your own device.
This tool does exactly that. When you drop a PNG here, your browser:
- Decodes the PNG natively — every browser includes a PNG decoder, so there is no decoder file to download and no waiting for a library to load. Animated PNGs decode to their first frame, and 16-bit-per-channel colour is decoded to 8 bits — both honest limits, stated on the file card.
- Reads the pixels, including the alpha channel — at 32-bit the alpha is written into the BMP, so transparency survives. At every other bit depth the image is opaque, so transparent pixels are flattened onto the background colour you picked.
- Re-encodes the pixels as a raw BMP with a pure-JavaScript BMP encoder — BITMAPINFOHEADER, bottom-up rows, at the bit depth you chose. Your original file is never modified.
What makes this converter different
The converters that top the results for this search mostly upload your files to a server (XConvert, FreeConvert, Zamzar and Convertio all convert server-side), and the client-side ones we found cap the bit depth — one offers only 24-bit output, another only a single file at a time. This page is the only dedicated PNG-to-BMP page we found that combines a batch of 20 files with a ZIP download, the full bit-depth range (1/8/16/24/32-bit), Floyd–Steinberg dithering, hardware and retro destination presets, a background colour choice for flattening transparency, 32-bit output that actually preserves the alpha channel, and a live network-request counter so you can verify the privacy claim yourself. It runs entirely in your browser — there is no server to upload to.
When is BMP the right choice for a PNG?
Almost never for sharing or storage — PNG is smaller and already lossless. BMP earns its place when the destination demands raw pixels: legacy Windows software and GDI tooling, printer utilities, embedded firmware and machine-vision rigs that read uncompressed data, and sprite or retro-game editors that load 1-bit or 8-bit BMPs. If the program you are feeding accepts anything else, use PNG to JPG for photos or keep the PNG.
Honest limitations
16-bit colour becomes 8-bit
The browser canvas decodes 16-bit-per-channel PNGs to 8 bits per channel. A 16-bit PNG converted here holds 8-bit colour — the fine gradations are rounded, and the tool warns you on the file card.
BMPs are much larger than PNGs
Expect roughly 6–20× the size for a 24-bit BMP of an image, and more at 32-bit. Every file shows its size multiple honestly, and the batch bar shows the total before you download anything.
APNG: first frame only
Animated PNGs convert from the first frame; the later frames are dropped. If you need the animation, keep the PNG — BMP has no animation at all.
16-bit output loses colour depth
16-bit BMP keeps 5 bits per channel — 32,768 colours instead of 16.7 million. Smooth gradients will band. Use it only when the destination insists on 16-bit.
8-bit and 1-bit are approximations
8-bit output is a 256-colour palette built by median cut; 1-bit is black and white only. Dithering fakes the missing shades by speckling pixels, but detail and smooth colour are lost either way.
Metadata is stripped
PNG text chunks and metadata, including location data, are dropped on re-encode. The BMP carries no metadata at all, only dimensions. PNG has no EXIF orientation tag, so the pixels come out exactly as stored.