HDR to WebP Converter
Convert HDR to WebP in your browser. HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation; WebP is the better fit for images on websites and in apps. You get a lossy WebP at the quality you choose (lossless under More options), keeping transparency. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
HDR expected · other image formats also work
How to use HDR to WebP
- 1
Add your HDR files: drop them here, choose them, or paste from the clipboard.
- 2
Set the quality. 80 to 85 is visually close to the original for most photos.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .webp files one at a time or together as a ZIP.
Why use Aback Images for hdr to webp
Where the WebP goes next
WebP opens in every current browser, Windows, macOS, Android, and recent Photoshop, GIMP and Affinity.
WebP next to HDR
A lossy WebP usually comes out far smaller than the HDR, which stores run-length encoded RGBE scanlines.
The first lossy pass
The HDR holds an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel with nothing discarded yet. This conversion is the first lossy encode these pixels see, and hard edges and flat colour show it first.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
HDR vs WebP
What changes from HDR to WebP
Encoding: the HDR uses run-length encoded RGBE scanlines; WebP uses lossy VP8 coding or lossless VP8L, and the download is a lossy WebP at the quality you choose (lossless under More options), keeping transparency.
Bit depth: an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel in the HDR; WebP allows 8 bits per channel, and the WebP written here has 8 bits per channel. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Colour: linear RGB (or XYZ in the XYZE variant) in the HDR; WebP supports RGB; lossy WebP stores colour at half resolution (4:2:0), written here as 8-bit sRGB.
Metadata: the HDR can carry a text header with FORMAT, EXPOSURE and optional comments; WebP can carry EXIF, XMP and ICC chunks, but nothing is copied across.
About HDR
Radiance .hdr stores high dynamic range light values, widely used for 3D environment maps and HDRI lighting.
A Radiance file starts with '#?RADIANCE' (or '#?RGBE'), text lines such as FORMAT=32-bit_rle_rgbe and EXPOSURE, a blank line, a resolution line like '-Y 2048 +X 4096', then the scanlines.
HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation.
About WebP
WebP is Google's web image format. It supports lossy and lossless compression, transparency and animation, and is typically 25 to 35 percent smaller than JPEG at the same visual quality.
A WebP is a RIFF file: 'RIFF', a length, 'WEBP', then chunks. A simple lossy file is one VP8 chunk and a lossless one is VP8L; the extended VP8X header announces alpha, animation, ICC, EXIF or XMP chunks.
When converting HDR to WebP makes sense
WebP is the better choice for images on websites and in apps, while HDR suits 3D lighting and environment maps.
WebP strengths: 25-35% smaller than JPEG; Transparency and animation in one format; Supported by every modern browser. Drawbacks to weigh: Some older desktop apps and photo printers cannot open it; Max 16383 px per side.
Limitations
- Light values above 1.0 are clipped rather than tone-mapped, so the sun and bright sky turn flat white.
- Environment maps are 2:1 equirectangular panoramas, so the picture looks stretched near the top and bottom, as it should.
- Files in the XYZE variant cannot be read here; RGBE files, the common kind, can.
- A few older desktop apps, print services and upload forms still reject WebP; keep a JPG or PNG copy for those.
- WebP images are limited to 16383 pixels on each side.
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Frequently asked questions
Does converting HDR to WebP lose quality?
WebP is lossy, so detail the eye barely notices is discarded to save space. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
What quality should I choose for WebP?
80 to 85 is visually close to the original for most photos. Go lower for thumbnails, or switch on Lossless under More options for screenshots and graphics.
Which apps open WebP files?
Every current browser, Windows, macOS, Android, and recent Photoshop, GIMP and Affinity.
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.