Add your HDR file
Drop one or more .hdr files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Converting a .hdr image to .avif re-encodes the pixels for a different balance of size, quality, and support. Free, private, and validated — the file never leaves your browser.
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.Converting a .hdr image to .avif re-encodes the pixels for a different balance of size, quality, and support. An .hdr file is a Radiance RGBE image, the original high-dynamic-range raster format. Each pixel stores three 8-bit mantissas and one shared 8-bit exponent, so 32 bits per pixel cover a luminance range no ordinary 8-bit format can express. It is still the everyday container for the HDRI environment maps used to light 3D scenes.
An .avif file stores a still image (or sequence) coded with the AV1 video codec inside a HEIF-derived container. It is currently among the most efficient image formats deployed on the web, routinely beating JPEG by half at similar quality while adding HDR, wide gamut, and alpha. For this route the practical draw is best-in-class compression among widely supported web formats and 10/12-bit HDR and wide-gamut color, which JPEG cannot represent — balanced against encoding is much slower than JPEG or WebP, especially at high effort settings, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .hdr, only about 1 percent precision per channel, and the shared exponent hurts saturated colours. Switching to .avif buys you best-in-class compression among widely supported web formats, which is why it is the better fit for serving hero images and photo galleries where bandwidth savings are significant. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Radiance HDR image (.hdr) | AVIF image (.avif) |
|---|---|---|
| Format type | Lossy — discards detail it judges invisible to shrink files | Lossy — discards detail it judges invisible to shrink files |
| How it stores data | rGBE encoding: three 8-bit mantissas plus one shared 8-bit exponent, 32 bits per pixel | encodes AV1 intra frames; both lossy and a mathematically lossless mode are defined |
| Strongest at | hDRI environment maps and sky domes for image-based lighting in Blender, Unreal, Unity and V-Ray | serving hero images and photo galleries where bandwidth savings are significant |
| Weak spot | only about 1 percent precision per channel, and the shared exponent hurts saturated colours | encoding is much slower than JPEG or WebP, especially at high effort settings |
| Metadata | the text header carries EXPOSURE, GAMMA, PRIMARIES, SOFTWARE and free-form comment lines. There is no EXIF, XMP or ICC profile block, and this converter's raster outputs do not carry the header lines across | eXIF and XMP are stored as metadata items in the HEIF container alongside ICC profiles or CICP color signaling, and mainstream encoders preserve them on conversion |
Drop one or more .hdr files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
Select .avif in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AVIF is selectable, the route is real and validated.
Press Convert. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid AVIF file. Outputs keep the original filename with the .avif extension.
A second lossy step always costs a little, because hdr is lossy-oriented and avif is lossy-oriented and each encoder discards detail differently (generation loss). At the default quality the difference is rarely visible; avoid repeated round-trips between .hdr and .avif.
Yes — the .hdr file is processed inside your browser tab and never uploaded. Decoding and re-encoding happen on your device using the browser's native image pipeline and hand-tuned encoders. Close the tab and the file is gone from memory.
Chrome 85+ (2020), Firefox 93+ (2021), and Safari 16+ (2022) render AVIF natively, covering the overwhelming majority of current browsers. On the desktop, macOS 13+ and Windows (via the AV1 Video Extension) preview it, but plenty of older editing and printing software cannot open it yet.
It depends on the content: encodes AV1 intra frames; both lossy and a mathematically lossless mode are defined. Convert one representative file first and compare before batch-processing a large set.
In .hdr, the text header carries EXPOSURE, GAMMA, PRIMARIES, SOFTWARE and free-form comment lines. There is no EXIF, XMP or ICC profile block, and this converter's raster outputs do not carry the header lines across. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.