Image format decider
The decider that tells you when to keep the JPEG.
Converters re-encode your image and name the smallest result. That is a different question. A 30% saving on an 8 kB logo is 2.4 kB — real, and not worth a change to your build. This one measures what each format costs your file, and reports the saving in a size you can weigh.
or drop one here. It stays in this tab — nothing is uploaded.
- Your image never leaves the tab
- libavif, libwebp, MozJPEG
- Free, no account
How to read the result
- The bar, not the percentage
- Each bar is drawn against your original, so a format that grew reads as a longer bar rather than as a minus sign you have to parse. Length is the comparison; the number is the confirmation.
- The saving is given in bytes
- A percentage hides the thing that decides: 40% off a 6 kB icon is 2.4 kB, which no build change is worth. The tool puts the saving next to a size you can picture — a network round trip carries about 14 kB before it has to wait for an acknowledgement.
- One quality number, three formats
- Quality 75 does not mean the same thing to libavif, libwebp and MozJPEG. These are three slightly different pictures at comparable settings, not one picture measured three ways — which is exactly why a single row cannot be a verdict.
- AVIF arrives last
- WebP and JPEG answer in about a second. AVIF is 3.3 MB of WebAssembly and lands behind them, so two of the three results are on screen while the third is still compiling. Nothing is waiting on a server.
Not yet answered. Which format wins at equal perceived quality — the size-over-quality curve — and what the switch costs in browser coverage and encoding time. That is the next milestone. It is named here rather than approximated, because a confident answer this tool cannot support would be the same move it was built to argue against.