BMP to QOI Converter
Processing entirely on your device — large files may take a moment.
Bitmap Image and Quite OK Image exist for different jobs: BMP is Windows’ native uncompressed bitmap format. Every pixel is stored exactly as captured, which makes files large but trivially simple to read — common in older software and scanners. QOI is popular with hobbyist engines and emulators; convert to PNG to view it anywhere.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How BMP compares to QOI
| BMP | QOI | |
|---|---|---|
| Compression | Usually none (RLE optional) | Lossless (RLE/delta) |
| Transparency | Rarely (V5 header only) | Supported |
| Animation | Not supported | Not supported |
| Metadata | Minimal | None |
| Best for | Legacy software and scanner output | Hobby engines, lossless simplicity |
How to convert BMP to QOI
- 1
Select your files
Drag & drop your BMP files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to QOI". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted QOI file individually, or grab everything at once as a ZIP archive.
About the BMP format
BMP is Windows' native bitmap format, dating to 1990. It stores pixels essentially raw — rows of BGR values padded to 4-byte boundaries — with optional RLE compression that almost nobody uses. That simplicity is its whole personality: any program written since the dawn of Windows can read one in a dozen lines of code, which is why scanners and ancient lab software still emit it.
The cost of that simplicity is size: an uncompressed BMP of a photo runs dozens of times larger than a JPG. There is no meaningful metadata standard, transparency only exists via the rarely-implemented V5 header, and no modern workflow needs it. Treat BMP as a legacy interchange format you convert away from.
+ Strengths
- ✓Zero compression artifacts — pixels stored as captured
- ✓Trivially easy to decode, even in ancient software
- ✓Universal inside the Windows world
! Limitations
- −Enormous files — dozens of times larger than JPG
- −No real metadata or color-management story
- −No role in modern web or print workflows
About the QOI format
QOI (Quite OK Image, 2021) is a lossless format defined in one short specification document: a stream of simple run-length and delta ops over linear pixels. An encoder fits in 300 lines, decodes faster than PNG, and compresses comparably for photographic content.
It has found a home in emulators, demoscene projects and hobby engines — anywhere people want images without a codec dependency. Viewers rarely support it, so converting QOI to PNG is the way to bring these files into normal tools.
+ Strengths
- ✓Radically simple spec (~200 lines)
- ✓Lossless with fast decode
- ✓No patent or licensing questions
! Limitations
- −Almost no viewer support
- −Larger than modern codecs for many images
Why convert BMP to QOI?
Converting makes sense where the strengths of QOI meet what BMP cannot give you. Radically simple spec (~200 lines) Meanwhile Enormous files — dozens of times larger than JPG One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this BMP to QOI converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting BMP to QOI?
No — QOI is a lossless format, so every pixel of the converted image matches your original BMP file. You can also adjust the quality/size balance before converting when the target format supports compression.
Will transparent areas survive the conversion to QOI?
Transparency is kept whenever QOI actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
Can I convert several BMP files at once?
Yes — drop as many files as you like into the tool and they are converted in one batch. When more than one file comes out, everything is bundled into a ZIP for a single download.