Convert an Image to AVIF
AVIF is the smallest mainstream image format going, regularly halving what WebP achieves on photographs. Encoding it in a browser is genuinely hard, though, and this free tool is candid about that: it verifies its own output and tells you the truth, all while your images stay entirely on your machine.
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How it works
- Add the JPG or PNG images you want in AVIF form.
- Set the quality level - AVIF stays impressive even at settings that would wreck a JPEG.
- Convert; the tool then inspects the output bytes to confirm real AVIF was produced.
- Download files that pass verification. If your browser could not encode AVIF, you are told plainly instead of being handed a fake.
Worth knowing
AVIF wraps still images in the AV1 video codec, and the results justify the hype: photographic content commonly lands 50% smaller than equivalent-quality JPEG, with cleaner rendering of gradients, film grain and dark regions. It carries alpha transparency, high bit depths and HDR. For decoding there is no catch left - Chrome, Firefox, Safari and Edge have all read AVIF for years now, so shipping .avif files to users is safe.
Encoding in a browser is the unsolved half, and it is where this page differs from most of what ranks beside it. The standard web API for saving canvas output, canvas.toBlob with the image/avif type, is allowed by the spec to ignore your request: when the browser has no AVIF encoder wired up - which is the common case even in 2026 - it silently returns a PNG instead. No error, no warning, just the wrong bytes. A converter that trusts the API blindly will save that PNG with an .avif extension and congratulate you.
This tool refuses to do that. After every encode it reads the output's actual bytes and checks the AVIF signature - a real file carries the marker ftypavif starting at byte 4. Output that fails the check is never dressed up as AVIF: you get a clear message that your browser could not encode the format, along with the honest alternatives - use WebP, which encodes reliably everywhere and captures most of the benefit, or produce AVIF with a native tool where browser limits do not apply.
When your browser does encode genuine AVIF, one habit matters: recalibrate your quality instincts. The AVIF quality scale is far more forgiving than JPEG's, and settings around 50-60 frequently deliver what JPEG needs 80-85 to reach. Start lower than feels safe and judge with your eyes - the file sizes will reward you.
Many online "AVIF converters" ship PNG files renamed .avif, because canvas.toBlob('image/avif') silently falls back to PNG in browsers without an encoder. You can expose them in any hex viewer: genuine AVIF shows ftypavif at byte 4, while the fakes open with the PNG signature. This tool performs that byte check on every file and never mislabels output.
What this tool will not do
- It will not pretend to encode AVIF when your browser cannot - unverifiable output is reported honestly, never renamed and delivered.
- It does not create animated AVIF or HDR/10-bit output; in-browser encoding is limited to standard 8-bit still images.
- It will not always beat WebP on non-photographic content - flat graphics sometimes compress no better, and screenshots occasionally favour WebP lossless.
Questions people ask
Is AVIF better than WebP?
For photographs, usually much better - 30-50% smaller at comparable quality, with superior handling of gradients and dark scenes. For flat graphics and text-heavy screenshots the gap narrows or reverses. The realistic answer is AVIF for photos, either format for graphics.
Can all browsers open AVIF files in 2026?
For viewing, yes - every major browser has decoded AVIF for years. Encoding is the weak side: most browsers still cannot create AVIF from script, which is why this tool verifies output rather than assuming the browser cooperated.
How do I check whether an AVIF file is real?
Open it in a hex viewer and look at the start: bytes 4 through 11 of a genuine file read ftypavif. If you see a PNG header instead, some converter renamed a PNG. This tool runs exactly that check automatically before offering any download.
What quality setting should I use for AVIF?
Around 50-60 for typical web photos - AVIF holds up at settings that sound alarmingly low if you are used to JPEG numbers. Compare the preview at a couple of settings; most people end up shipping smaller files than they initially dared.
Why did the tool tell me my browser cannot encode AVIF?
Because it tried, checked the resulting bytes, and found the browser substituted PNG - the silent fallback the canvas API permits. That message is the tool working correctly. Your practical options are converting to WebP here, or using desktop software for the AVIF encode.
Should I convert every image on my site to AVIF?
Photographs, yes, ideally with a WebP or JPEG fallback via the picture element for belt and braces. Logos and UI graphics gain less and are often better as SVG or lossless WebP. Measure a representative sample before batch-converting a whole library.
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