CONVERT
FITS → WEBP
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Fast, secure FITS to WEBP conversion. No registration required.
Setup: FITS is a raster image format with its own balance of compression, colour depth, and software support. Goal: an interchangeable WEBP. A FITS → WEBP operation is one of the simplest image jobs there is: same pixel grid, different wrapper. What genuinely changes is how lossy the codec is, whether alpha survives, and how large the final file ends up. KaijuConverter picks safe defaults for each of those and lets you override them under Advanced. A quick refresher — FITS is a raster image format with its own balance of compression, colour depth, and software support. By contrast, WebP is Google's modern image codec offering smaller files than JPEG and PNG at similar quality.
FITS Astronomical Image
Source formatFITS (Flexible Image Transport System) is the standard digital file format in astronomy for storing images, tables, and metadata from telescopes and satellites. It supports multi-dimensional arrays and extensive header metadata for scientific observation records.
WebP Image
Target formatWebP is a modern image format developed by Google that provides superior lossless and lossy compression. Files are typically 25-35% smaller than equivalent JPEG or PNG images at the same visual quality.
Why convert FITS to WEBP
The real reason to move from FITS to WEBP is almost never picture quality — both raster formats store essentially the same pixels. It is about the tools downstream: which editors open the file natively, which CMSes upload it without transcoding, which social platforms accept it. Picking WEBP solves those edge cases at the cost of a short conversion step.
HOW TO CONVERT
FITS → WEBP
Provide the FITS
Click or drag to upload. We accept a single FITS file per job, with an optional queue of additional images for batch mode.
Encode to WEBP
The conversion decodes the FITS, resolves the colour space to sRGB and writes the WEBP container around the pixel data.
Save the WEBP
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all WEBP outputs is produced instead.
Common Use Cases
Share across platforms
Send WEBP files to anyone without worrying about whether they have the right software for FITS.
Embed in documents
Drop WEBP output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
WEBP often produces smaller files than FITS for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
FITS vs WEBP — Strengths and limitations
What each format does best, and where it falls short.
FITS Strengths
- Self-documenting — every file carries complete observational metadata.
- Lossless — bit-exact storage of detector readouts.
- Stable since 1981 with zero breaking changes.
- Mandatory for professional astronomy — every research publication uses it.
- Open standard endorsed by IAU.
Limitations
- Niche — used almost exclusively in astronomy.
- File sizes are large (no default compression).
- Not a display format outside specialized viewers (DS9, AstroBin).
WEBP Strengths
- Smaller file sizes than JPEG, PNG, and GIF at equivalent visual quality.
- Single format for lossy photos, lossless graphics, transparency, and animation.
- Full alpha channel support with smaller files than PNG.
- Now universally supported in all modern browsers.
- Open-source reference implementation (libwebp) by Google.
Limitations
- Some older software and image editors still don't read WebP natively.
- Max dimensions are 16,383 × 16,383 — lower than JPEG or PNG.
- Print workflows rarely support WebP (no CMYK, limited color management).
FITS vs WEBP — Technical specifications
Side-by-side comparison of the technical details.
FITS
- MIME type
- image/fits
- Extensions
- .fits, .fit, .fts
- Standard
- IAU-endorsed FITS 4.0 (latest revision)
- Header records
- 80-character ASCII cards
- Encoding
- IEEE big-endian integers and floats
WEBP
- MIME type
- image/webp
- Compression
- VP8 (lossy) or VP8L (lossless)
- Color depth
- 8 bits per channel
- Max dimensions
- 16,383 × 16,383 pixels
- Transparency
- Full 8-bit alpha channel
- Animation
- Supported since WebP 2012 revision
| Specification | FITS | WEBP |
|---|---|---|
| MIME type | image/fits | image/webp |
| Extensions | .fits, .fit, .fts | — |
| Standard | IAU-endorsed FITS 4.0 (latest revision) | — |
| Header records | 80-character ASCII cards | — |
| Encoding | IEEE big-endian integers and floats | — |
| Compression | — | VP8 (lossy) or VP8L (lossless) |
| Color depth | — | 8 bits per channel |
| Max dimensions | — | 16,383 × 16,383 pixels |
| Transparency | — | Full 8-bit alpha channel |
| Animation | — | Supported since WebP 2012 revision |
FITS vs WEBP — Typical file sizes
Approximate file sizes for common scenarios.
FITS
- Backyard-telescope CCD shot (5 MP) 10-30 MB
- Hubble WFC3 single exposure ~65 MB
- JWST NIRCam full detector ~650 MB
WEBP
- Web photo (vs JPEG equivalent) 25–35% smaller
- Transparent logo (vs PNG) 20–30% smaller
- Animated replacement for GIF 60–80% smaller
- Hero banner (1920×1080) 150–400 KB
Quality & Compatibility
FITS-to-WEBP conversion does not change the visible content. Quality is capped by the FITS decode; re-encoding a lossy source at high quality cannot recover detail that was already discarded. For archival masters, keep the original FITS alongside the WEBP copy.
Tips for Best Results
- Large FITS files may look identical to small WEBP files for photographic content; pick quality based on end use, not headline megapixels.
- For print, export WEBP at 300 DPI minimum and check that the colour profile embedded matches the print shop specification.
- Batch-convert related FITS images in one pass so they share identical encoder settings and look consistent side-by-side.
Frequently Asked Questions
It depends on the codecs involved. If both FITS and WEBP are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If WEBP is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded FITS exactly, but cannot recover detail that FITS had already compressed away.
Often yes, especially when WEBP is lossless. FITS tuned for efficient web delivery will usually produce smaller files than WEBP's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
WebP Image Format: Google's Modern Image Standard Explained
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Read guideWebP Image Format Guide
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Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.