ARW vs WEBP
A detailed comparison of Sony RAW ARW and WebP Image — file size, quality, compatibility, and which format to choose for your workflow.
Sony RAW ARW
Raster & Vector ImagesARW is Sony Alpha RAW format for professional and mirrorless cameras.
About ARW filesWebP Image
Raster & Vector ImagesWebP 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.
About WEBP filesStrengths Comparison
ARW Strengths
- Full 14-bit sensor data on flagship bodies.
- Rich Sony metadata (Creative Style, DRO, Focus Magnifier).
- Supported by every major raw processor.
- Lossless compression available on modern bodies.
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
ARW Limitations
- Proprietary — new Sony body launch = Lightroom update required.
- Lossy compression was the only option on many older bodies (visible banding in highlights).
- File sizes are huge on 50+ MP bodies.
- Some ARW variants use 16-bit layout that breaks older third-party tools.
WEBP 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).
- Editing tools are less mature than JPEG/PNG; round-tripping can lose quality.
Technical Specifications
| Specification | ARW | WEBP |
|---|---|---|
| MIME type | image/x-sony-arw | image/webp |
| Extension | .arw | — |
| Container | TIFF/EP with Sony MakerNote tags | — |
| Bit depth | 14-bit (flagship); 12-bit (entry) | — |
| Compression | Uncompressed, Lossless, Lossy | 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 |
Typical File Sizes
ARW
- 24 MP ARW (A7 III, A7C) 25-45 MB
- 42 MP ARW (A7R III) 50-90 MB
- 61 MP ARW (A7R IV, A7R V) 75-130 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
Ready to convert?
Convert between ARW and WEBP online, free, and without installing anything. Encrypted upload, automatic deletion after 2 hours.
Frequently Asked Questions
ARW (Sony RAW ARW) is an image format used to store raster graphics — a two-dimensional grid of pixels describing a picture. It is part of the raster & vector images family and designed around a specific trade-off between file size, visual fidelity, and feature support (transparency, colour depth, compression type). Photographers, web designers, and content creators choose ARW when its particular strengths match the publishing target.
WebP is a modern image format developed by Google in 2010. It supports both lossy and lossless compression, transparency, and animation, while delivering files 25-35% smaller than JPEG and PNG equivalents.
Most desktop photo viewers (Windows Photos, macOS Preview, GIMP, Photoshop, Affinity Photo) open ARW natively. On mobile, iOS Photos and Google Photos display ARW in the gallery when supported by the OS. If the format is rare or new, convert to JPG or PNG first — both are universally readable — using our ARW to JPG or ARW to PNG converter.
WebP files open natively in Chrome, Firefox, Safari, Edge, and most modern image viewers. On Windows, the Photos app supports WebP. On macOS, Preview handles it from macOS Big Sur onward.
Upload the ARW to KaijuConverter and pick a target format (JPG, PNG, WebP, HEIC, TIFF, BMP, SVG, PDF). The conversion runs in the browser via ImageMagick and returns a download in seconds. No account or installation required; both input and output delete automatically within two hours.
It depends on the task. JPG is the smallest file size for photographs; PNG is lossless with transparency; ARW has its own niche that may favour colour depth, animation, or encoding efficiency over one or both of those. For the final web publish, test all three and measure file size plus visible quality on real content.