BMP to DDS Converter
Convert BMP to DDS in your browser. BMP files usually come from Windows Paint, legacy Windows programs, embedded displays and some scanners; DDS is the better fit for game textures and mods. You get an uncompressed 32-bit RGBA DDS texture with a single mip level, or DXT1 or DXT5 block compression if you choose it. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
BMP expected · other image formats also work
How to use BMP to DDS
- 1
Add your BMP files: drop them here, choose them, or paste from the clipboard.
- 2
Choose the DDS compression: none for an exact 32-bit texture, DXT1 or DXT5 for smaller GPU-ready files.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .dds files one at a time or together as a ZIP.
Why use Aback Images for bmp to dds
Where the DDS goes next
DDS opens in game engines, Visual Studio, Paint.NET, GIMP, NVIDIA and Intel texture tools.
DDS next to BMP
The DDS is written uncompressed, so expect it to be several times larger than the BMP, which stores usually none; RLE for some 4 and 8-bit files.
Written without a lossy pass
The DDS is written uncompressed, so the pixels decoded from the BMP arrive unchanged.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
BMP vs DDS
What changes from BMP to DDS
Encoding: the BMP uses usually none; RLE for some 4 and 8-bit files; DDS uses block compression (BC1 to BC7, also called DXT) or uncompressed RGBA, and the download is an uncompressed 32-bit RGBA DDS texture with a single mip level, or DXT1 or DXT5 block compression if you choose it.
Bit depth: 1, 4, 8, 16, 24 or 32 bits per pixel in the BMP; DDS allows 8 bits per channel for common texture formats, and the DDS written here has 8 bits per channel.
Colour: RGB or an indexed palette in the BMP; DDS supports RGB(A); normal maps and packed masks store data rather than colour, written here as 8-bit sRGB.
Transparency: the BMP stores it as an optional fourth byte in 32-bit files, which many programs ignore; the DDS keeps it as alpha inside the compressed blocks (BC2, BC3, BC7) or a 1-bit cut-out (BC1).
Metadata: the BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers); DDS can carry a 128-byte header (plus a DX10 header) describing the pixel format, nothing about the picture, but nothing is copied across.
About BMP
BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.
A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.
BMP files usually come from Windows Paint, legacy Windows programs, embedded displays and some scanners.
About DDS
DDS is a GPU texture format used by DirectX games. It stores block-compressed textures (DXT/BC) and mipmaps that graphics cards decode directly.
A DDS file starts with 'DDS ' and a 124-byte header giving the size, mipmap count and pixel format: a FourCC such as DXT1 or DXT5, or 'DX10' followed by an extra header naming a DXGI format. The largest mipmap comes first.
When converting BMP to DDS makes sense
DDS is the better choice for game textures and mods, while BMP suits legacy software and embedded systems that require it.
DDS strengths: Loads straight into GPU memory; Mipmaps included. Drawbacks to weigh: Not viewable outside game tools; Lossy block compression.
Limitations
- BMP stores nearly every pixel literally, so almost any compressed target is several times smaller.
- A 32-bit BMP can carry an alpha byte that most programs ignore; if the image suddenly gains transparent areas after converting, that byte was set.
- The DDS has a single mip level, so generate mipmaps in your engine or texture tool if it needs them.
- Uncompressed DDS textures take 4 bytes per pixel; DXT1 is an eighth of that and DXT5 a quarter, at the cost of lossy 4×4 block compression.
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Frequently asked questions
Does converting BMP to DDS lose quality?
DDS is written uncompressed, so the pixels are stored exactly as decoded.
Is transparency kept in the DDS?
Yes. BMP stores it as an optional fourth byte in 32-bit files, which many programs ignore, and the DDS is written with an alpha channel, so transparent areas stay transparent.
Which apps open DDS files?
Game engines, Visual Studio, Paint.NET, GIMP, NVIDIA and Intel texture tools. It does not open in web browsers.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.