FITS to BMP Converter
Processing entirely on your device — large files may take a moment.
Some legacy Windows programs, industrial devices and printers still require plain, uncompressed BMP files. If your files are still in FITS format, this page is the shortcut: FITS (Flexible Image Transport System) is the data format of professional astronomy — every image carries a human-readable header with telescope, exposure and world coordinates alongside the raw pixel data.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How FITS compares to BMP
| FITS | BMP | |
|---|---|---|
| Compression | None (optionally Rice/GZIP) | Usually none (RLE optional) |
| Transparency | Not supported | Rarely (V5 header only) |
| Animation | Not supported | Not supported |
| Metadata | Rich text header (WCS) | Minimal |
| Best for | Telescope frames, science data | Legacy software and scanner output |
How to convert FITS to BMP
- 1
Select your files
Drag & drop your FITS 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 BMP". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted BMP file individually, or grab everything at once as a ZIP archive.
About the FITS format
FITS (Flexible Image Transport System) has carried professional astronomy data since 1981: every file opens with a plain-text header that records telescope, instrument, exposure, filters and world coordinates, followed by raw pixel arrays — often 16-bit or float, sometimes data cubes.
Values can be negative or far above display range, so FITS never looks right in a photo viewer. Converting to PNG applies a simple scaling pass that reveals the nebula or galaxy in the numbers — good for previews, while science pipelines keep the original.
+Strengths
- ✓Self-documenting science headers
- ✓High bit depth (16/32-bit, float)
- ✓The standard of every observatory
!Limitations
- −Not display-ready
- −Files are large and uncompressed
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
Why convert FITS to BMP?
Think of it as moving your file to the container that fits the job. Not display-ready BMP works differently: Zero compression artifacts — pixels stored as captured If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this FITS to BMP 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 FITS to BMP?
No — BMP is a lossless format, so every pixel of the converted image matches your original FITS file. You can also adjust the quality/size balance before converting when the target format supports compression.
Can I convert several FITS 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.
Will transparent areas survive the conversion to BMP?
Transparency is kept whenever BMP 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.