In-browser image optimizer
Convert images to AVIF
AVIF is the codec that made “half the size of WebP” real for photographs. Encoding it used to mean installing tools; here it runs as WebAssembly in the tab, next to WebP and JPEG so you can judge the trade-off yourself.
Make an AVIF in three steps
- Open a JPG or PNGAny image the browser can decode works as a source — including HEIC photos on Safari.
- Set the right pane to AVIFStart at quality 50–60. AVIF at 55 usually matches JPEG at 85 while being far smaller; move the slider and watch both the size and the preview.
- Check the fallbackAVIF is not universal on older devices, so serve it through <picture> with a WebP or JPEG fallback. This page generates both if you need them.
AVIF vs WebP vs JPEG
For photographs at matched visual quality, AVIF typically produces files 20–50% smaller than WebP and 50–70% smaller than JPEG. The cost is encoding time and weaker support in older software — neither of which matters when the alternative is a slower page.
Encoding speed
AVIF encoding is genuinely slow, which is why doing it locally is attractive: no upload wait, no queue, no per-image quota. Use fewer threads if your laptop gets hot.
What to expect
| Codec | Size vs JPEG | Browser support | Encode speed |
|---|---|---|---|
| JPEG | — | Everything | Fast |
| WebP | 30–60% smaller | All modern browsers | Fast |
| AVIF | 50–70% smaller | Chrome, Firefox, Safari 16+ | Slow |
| JPEG XL | 50–65% smaller | Newer builds, still not universal | Medium |
Questions
Is AVIF better than WebP?
At the same visual quality AVIF is usually 20–50% smaller for photographs. WebP remains a safer default because every modern browser and tool reads it.
Does AVIF support transparency?
Yes, AVIF has an alpha channel — this converter keeps it when the source has one.
Why is encoding so slow?
AVIF’s compression is far more expensive than JPEG’s. A large photo can take several seconds even with multiple threads, all of it on your machine.