Different jobs, different formats
HEIC, WebP and AVIF are often lined up as rivals, but they were built for different places. HEIC is what iPhones write to storage. WebP and AVIF are formats for delivering images on the web. Choosing between them starts with where the file is going, not with which is “best”.
What each one is
HEIC is a HEIF container with HEVC-compressed image data. HEVC is patent-encumbered, which is a large part of why browser and OS support is patchy; the HEIC vs HEIF guide covers the container side.
WebP is Google’s format. MDN’s image format guide says it supports lossy compression (based on the VP8 video codec) and lossless compression, plus transparency and animation, and reports lossy WebP as on average 25-35% smaller than JPEG at visually similar quality. The container is documented in the WebP container specification. Treat the MDN figure as an average, not a promise for your photo.
AVIF stores AV1-compressed images in the HEIF container; the AVIF specification defines that storage. MDN describes it as open and royalty-free, with lossy and lossless modes, alpha, HDR and wide colour gamut support, and says it generally compresses better than WebP. MDN also notes AVIF has no progressive rendering, so the file must download completely before it displays.
Browser support
Support moves, so check live tables instead of this page: Can I use: WebP, Can I use: AVIF and Can I use: HEIF. MDN lists WebP and AVIF as supported in current Chrome, Edge, Firefox, Opera and Safari, and neither it nor this site claims the same for HEIC. MDN’s recommendation for the web is to offer a JPEG or PNG fallback with the <picture> element when you use WebP or AVIF.
Transparency and photos
Photos rarely need transparency, but if the source does, remember the differences:
- WebP and AVIF keep an alpha channel. FromHEIC’s HEIC to WebP and HEIC to AVIF keep alpha when the HEIC has one.
- JPG does not, and flattens to white in our converter.
- HEIC outputs written by FromHEIC do not carry alpha; transparency is flattened onto a background you choose, with a warning.
Choosing, by situation
Publishing on your own website. Use WebP or AVIF with a JPEG fallback. AVIF tends to produce smaller files; WebP is the simpler default. FromHEIC’s AVIF encoder runs as single-threaded WebAssembly, so expect it to be slow on large images. Pick an AVIF quality by looking at the output, since there is no universal setting; the converter defaults to 60 for AVIF and 82 for WebP and shows a size comparison.
Sending to someone. Use JPG. It is accepted nearly everywhere. AVIF cannot be read by very old software. HEIC vs JPG explains the compatibility trade.
Archiving originals. Keep the HEIC. Re-encoding into WebP or AVIF is a further lossy step on top of an already-compressed file.
Editing. Use a lossless or uncompressed output, such as PNG or TIFF, not WebP or AVIF at low quality.
CMS uploads. Check what your platform accepts. See WordPress and Shopify.
Lossy-on-lossy
Any HEIC to WebP or AVIF conversion decodes the HEIC and compresses the pixels again. If you plan to do that, convert once, from the original, and keep the original. Do not convert a WebP to an AVIF to a JPG in a chain; every hop adds loss.
Animations
Animated WebP and AVIF exist, but FromHEIC’s WebP/AVIF-to-JPG tools convert only the first frame. If animation matters, keep the source animated file.
Try it
Convert a single photo to each format at default settings with the WebP tool, the AVIF tool and the JPG tool, then compare the sizes shown. For existing web images, the image compressor works on JPEG, PNG, WebP and AVIF. More size advice is in reducing photo size.