What Is AVIF?
AVIF is a still image saved with AV1, the royalty-free video codec, in the same container family as Apple's HEIC. It is the smallest mainstream image format on the web: at the same measured quality, the photos on this page came out 33–71% smaller than JPEG and 24–48% smaller than WebP. Here is what the format is, what it costs you, and how to open one.
AVIF vs WebP vs JPEG, Measured
Every number here was produced by running this site's own converter over the three stock photos in this repository — not estimated, and not copied from anyone else. Comparing formats at the same slider setting is meaningless, because a "75%" in one codec is not a "75%" in another. So we swept each encoder across eleven quality settings, measured the PSNR of every output against the exact pixels the encoder saw, and read off the file size each format needs to hit the same measured quality — 40 dB, the level usually called visually lossless.
| Test photo (all at 40 dB PSNR) | JPEG | WebP | AVIF | AVIF vs JPEG |
|---|---|---|---|---|
| dslr-camera.jpg1600×2000 | 116.0 KB | 60.7 KB | 40.6 KB | 65% smaller |
| hero-memory-card.jpg1600×1067 | 68.0 KB | 37.4 KB | 19.4 KB | 71% smaller |
| photo-grid.jpg1400×931 | 252.1 KB | 222.7 KB | 169.4 KB | 33% smaller |
The spread is the story. On the two ordinary photographs AVIF is dramatic — a 68 KB JPEG's worth of quality fits in 19.4 KB. On photo-grid.jpg, a dense collage of fine detail and hard edges, the lead narrows to 33%. AVIF is at its best on smooth, photographic content and at aggressive compression; it is at its weakest on busy, high-frequency images pushed to high quality. Averaging those two cases into one marketing number would hide exactly the thing worth knowing.
What the Comparison Table Usually Leaves Out
Three things showed up in the sweep that the usual format round-up never mentions:
- The quality slider lies across formats. On
dslr-camera.jpgat a 75% setting, WebP produced 81.5 KB and AVIF produced 124.2 KB — AVIF looks worse until you notice it also measured 45.5 dB against WebP's 41.2 dB. It spent the extra bytes on quality you asked for. Compare formats at matched quality, never at matched slider. - AVIF here has no lossless setting. This converter encodes 8-bit, 4:2:0 AVIF, so even 100% quality loses a little: we measured the ceiling at 67.6, 54.2 and 45.8 dB on the three photos. WebP at 100%, by contrast, came back bit-exact. If you need a pixel-perfect file, PNG is the format to reach for.
- Encoding is genuinely slow. On the 3.2-megapixel test photo, JPEG took about 0.17 s, WebP about 0.5 s, and AVIF about 5.1 s — roughly 30× the JPEG time. The first AVIF conversion also pulls down a 3.3 MB WebAssembly encoder, because no browser can encode AVIF from a canvas by itself.
What AVIF Can Do That JPEG Can't
| JPEG | WebP | AVIF | |
|---|---|---|---|
| Underlying codec | JPEG (1992) | VP8 | AV1 |
| Transparency | No | Yes, 8-bit alpha | Yes, up to 12-bit alpha |
| Animation | No | Yes | Yes (image sequences) |
| Colour depth | 8-bit | 8-bit | 8, 10 and 12-bit |
| HDR | No | No | Yes |
| Browser support (caniuse) | Universal | 96.07% | 93.4% |
| Encode time, 3.2 MP photo | ~0.17 s | ~0.5 s | ~5.1 s |
| Licensing | Royalty-free | Royalty-free | Royalty-free |
Browser and Device Support
caniuse currently puts full AVIF support at 93.4% of global traffic, against 96.07% for WebP. Every current major browser decodes it:
- Chrome: since 85 (2020)
- Firefox: since 93 (2021)
- Safari: since 16.4 (March 2023), including iOS — 16.1 to 16.3 handle still images only, and need macOS 13 or later
- Edge: since 121 (2024)
- Opera 71 and Samsung Internet 14 and up
That is high enough to serve AVIF as the primary asset behind a <picture> element with a WebP or JPEG fallback, but not high enough to drop the fallback. Outside the browser the picture is rougher: a good deal of desktop software, print workflows and upload forms still refuse .avif, which is the everyday reason someone lands here needing to convert one back to something ordinary.
When to Use AVIF
Photographs on a website — yes
This is what AVIF is for. Hero images and content photos are the largest assets on most pages, and halving them (or better) is the single biggest win available. Serve it from a <picture> element with a WebP or JPEG fallback.
Encoding on a server hot path — no
At roughly 30× JPEG's encode time, AVIF belongs in a build step or an offline batch, not in a request handler resizing an upload while the user waits.
Masters and archives — no
AVIF is a delivery format. Keep a lossless master (PNG, TIFF, or your camera's RAW) and re-export when the next format arrives — especially since the AVIF written here is 4:2:0 and never bit-exact.
Anything you have to hand to someone else — probably not
Email attachments, print shops, client deliverables, job applications: if the recipient's software chokes, the 40 KB you saved cost you an afternoon. Send JPG or PNG.
Replacing an animated GIF — measure first
AVIF stores animation and can beat GIF badly on real video-like content. But converting a GIF to AVIF in a browser can also make a mostly-static clip larger, because no browser exposes a real AV1 video encoder. That page has the measured numbers.
How to Convert To and From AVIF
Both directions run entirely in your browser here — nothing is uploaded. They work differently under the hood, and the difference is worth knowing:
- Converting to AVIFuses libavif compiled to WebAssembly, so it works even in a browser that cannot display AVIF. Expect a few seconds per photo and a one-time 3.3 MB encoder download.
- Converting from AVIFleans on your browser's own AVIF decoder. Any browser from the support list above will open the file; a very old one will not be able to read your .avif at all.
Open an AVIF file as something else
Make an AVIF from something else
Convert AVIF in Your Browser
Drop your images in and pick the output format. Free, private, runs entirely in your browser — no uploads, no signups.
Open the Image ConverterFrequently Asked Questions
What is an AVIF file?
An AVIF file is a still image compressed with AV1 — the video codec built by the Alliance for Open Media — and stored in the same HEIF container family that Apple's HEIC uses. In effect it is a single frame of AV1 video saved as a picture. The format was published in 2019, it is royalty-free, and it uses the .avif extension. Because it borrows a modern video codec's compression, it produces much smaller files than JPEG at the same visual quality.
Is AVIF better quality than JPEG?
At the same file size, yes, by a wide margin. We measured it by converting three stock photos with this site's own encoders and comparing each output against the exact pixels the encoder saw. Matched at 40 dB PSNR, JPEG needed 116.0 KB, 68.0 KB and 252.1 KB on our three test photos, where AVIF needed only 40.6 KB, 19.4 KB and 169.4 KB — 33% to 71% fewer bytes for the same measured quality. The catch is that AVIF as encoded here subsamples chroma at 4:2:0 and has no lossless mode, so at the very top of the quality range JPEG can still resolve detail AVIF cannot.
Is AVIF better than WebP?
On compression, yes. At 40 dB PSNR on our three test photos, AVIF came in 24% to 48% smaller than WebP from the same source pixels. WebP wins on two practical points: it encodes roughly ten times faster, and at 100% quality this converter's WebP output is bit-exact lossless, which AVIF here never is. WebP also has slightly wider browser support (96.07% versus 93.4% on caniuse).
Which browsers and devices can open AVIF?
As of this writing caniuse puts full AVIF support at 93.4% of global traffic: Chrome since 85 (2020), Firefox since 93 (2021), Safari since 16.4 (March 2023, on iOS too), Edge since 121 (2024), Opera since 71, and Samsung Internet since 14. Safari 16.1 to 16.3 supports still AVIF only and needs macOS 13 or later. Outside the browser, support is patchier — plenty of desktop editors and upload forms still reject .avif files, which is the usual reason people need to convert one.
Why does AVIF take so long to convert?
Because AV1's encoder searches much harder for redundancy than JPEG's does, and that search is exactly what buys the small file. On this site's 1600x2000 test photo at 75% quality, JPEG encoded in about 0.17 seconds, WebP in about 0.5 seconds, and AVIF in about 5.1 seconds. The first AVIF conversion in a session also downloads a 3.3 MB WebAssembly encoder, because no browser can encode AVIF from a canvas on its own.
Can AVIF do transparency and animation?
Yes to both. The format carries a full alpha channel — at up to 12 bits, richer than PNG's 8-bit alpha — and supports image sequences, so an animation can be stored as an AVIF instead of a GIF. It also supports 10- and 12-bit colour and HDR, which JPEG and WebP cannot do at all.
Is AVIF lossless?
The format has a lossless mode, but this converter's encoder does not use it: AVIF output here is 8-bit and 4:2:0 chroma-subsampled, so even the 100% setting loses something. We measured the ceiling on our three test photos at 67.6 dB, 54.2 dB and 45.8 dB PSNR — visually indistinguishable in the first two cases, but not bit-exact. If you need a truly lossless file, convert to PNG instead.
Related Reading
- WebP vs AVIF: which should you use? — the head-to-head, including the picture-element fallback chain that ships AVIF safely.
- JPG to AVIF — why re-encoding a photo that is already a JPEG saves almost nothing at the default quality, and what to set the slider to instead.
- Best image format by use case — a decision guide for web, print, email, and archive.
- How to compress images without losing quality — the quality settings and format choices that shrink files invisibly.
How these numbers were produced: each of the three photos in this site's public/images folder was converted to JPEG, WebP and AVIF by this site's own converter running in headless Chrome, at eleven quality settings per format. PSNR was measured against the pixels the encoder saw, and the file size at 40 dB was interpolated between the two bracketing settings. The photos are themselves JPEGs, so all three encoders are compressing pixels that already carry JPEG artefacts — a lossless master would flatter AVIF further.