Convert / JPG to WebP
Convert JPG to WebP Online
Re-encode JPG photos as WebP for dramatically smaller files at the same visible quality, plus the transparency and animation JPG has never supported. Runs in your browser with no upload.
Why Convert JPG to WebP?
Most JPGs carry a lot of slack
Camera and export JPGs are rarely stored efficiently. Re-encoding our 5.4 MB test photo to WebP at visually identical quality left 1.0 MB, an 82% saving.
Better Core Web Vitals
Images are usually the largest element on a page. Smaller ones move Largest Contentful Paint directly.
Universal browser support
Chrome, Firefox, Safari and Edge have all shipped WebP since 2020. Only pre-2020 browsers need a JPG fallback.
No upload required
The re-encode runs on your device through canvas, so it is instant and exempt from the daily limit.
JPG vs WebP, measured
WebP is usually sold as a 25 to 35% saving over JPG. Our own numbers do not support that, and it is worth being straight about why. The large saving you get converting a photo is real, but it comes from re-encoding a wastefully stored JPG, not from WebP being a dramatically better codec. Given the same photo and a good JPEG encoder, the two formats land within a few percent of each other.
| Measure | Your source JPG | WebP | JPG, re-encoded |
|---|---|---|---|
| File size | 5,486 KB | 1,006 KB | 983 KB |
| Saving against the source | -- | 82% smaller | 82% smaller |
| Quality against the source (SSIM) | 1.000 | 0.989 | 0.990 |
| Transparency | No | Yes | No |
| Animation | No | Yes | No |
| Opens in anything, any age | Yes | Since 2020 | Yes |
One 3840 x 2160 photograph, 5.4 MB as supplied. WebP written at quality 92 and the third column through mozjpeg at quality 90, the settings at which both score the same structural similarity, so the columns compare like for like. The converter itself writes a photograph at quality 80, which comes out below the figure here. So the honest reason to pick WebP is transparency, animation and flat-colour graphics, where it genuinely wins. On photographs alone, a well-encoded JPG is competitive.
Questions
What quality is the WebP written at?
It depends on the image, because a single number is wrong for half of them. A photograph is written at quality 80, where the difference is not something you find by looking. A flat graphic takes the other branch: lossless on the server, quality 92 in your browser, because lossy encoding costs a screenshot more in visible edge artefacts than it ever saves in bytes. Encoding everything losslessly was the old behaviour and it produced photos larger than the JPG they came from, defeating the point.
Am I losing quality by re-encoding?
Slightly. The JPG was already lossy, and WebP re-compresses that result. At quality 80 the second generation is hard to see on a photograph, but keep your original if you may need to re-edit.
Should I still serve a JPG fallback?
Only if you support browsers older than 2020. Otherwise a plain <img> pointing at the WebP is fine. Use a <picture> element if you need both.
Does this work for many files at once?
Yes. Up to 10 per batch, all converted locally, with a ZIP download for the set.
This one never leaves your device
Your browser does this conversion itself, with no upload and nothing counted against the daily limit. Close the tab mid-way and the file was never anywhere but your machine.
What the privacy policy saysFurther reading
Explainer8 minThe attachment limit is not the number you were toldMail systems advertise one size and enforce a smaller one. Where the missing quarter of your budget goes, and what to do about a photo folder that will not send.Architecture10 minWe built the same converter twice, and the two disagreeHalf of this site converts in your browser and half on our server. Measuring them against each other found the speed win we expected and three output differences we did not.Speed up your pages
On our test photograph WebP left 18% of the bytes at a matched similarity score. Yours will differ; the direction will not.