What you get
The table converts three WebP files to JPEG at quality 88. The photo grew from 403 KB to 439 KB, the screenshot from 29 KB to 66 KB, and the illustration from 31 KB to 43 KB. JPEG is usually bigger than the WebP it comes from, because WebP is the more efficient format. You convert for compatibility, not for size.
| Test image | WebP | JPEG | Fidelity (PSNR) | Time |
|---|---|---|---|---|
| Photo | 403 KB | 439 KB | 35.2 dB | 626 ms |
| Screenshot | 29 KB | 66 KB | 42.8 dB | 196 ms |
| Illustration (alpha) | 31 KB | 43 KB | 46.8 dB | 201 ms |
The WebP inputs were made from the test images at quality 80. JPEG has no transparency, so see-through areas of the illustration are filled with the background colour. Flat graphics usually get larger as JPEG. Timings: one thread of WebAssembly on Node v22.23.4, Intel(R) Xeon(R) Processor @ 2.10GHz, 2 cores, measured 2026-10-31. Other devices will differ.
Transparent WebP files
JPEG cannot store transparency. Any see-through area is filled with the background colour, white by default, which you can change in Advanced settings, under Format and quality. Pick a colour that suits the artwork: dark logos on white, light logos on a dark colour. The same colour is used if you add padding in the resize tool.
Choosing the quality
Quality 88 is a balanced default. A lossy WebP converted to JPEG goes through a second lossy step, so raise the quality to 92 or higher if the picture has fine detail you care about. For a WebP that was lossless, quality 90 is a good place to start.
Where JPEG is still required
- Government and exam forms and job portals that list JPG as the only format.
- Older desktop software and some print kiosks.
- Marketplaces and uploaders that reject WebP.
If you also need the file under a size limit, use the size target pages and set the output to JPEG.
Animated WebP
An animated WebP is read as its first frame. JPEG has no animation, so the result is a still image.
Which quality for which use
- 85 to 90 for sharing photos and uploading to forms.
- 92 to 95 when the picture has fine detail, small text or hard edges, or will be edited again.
- Around 75 to 80 only when a size limit forces it. A target size, set under File size in Advanced settings, picks the quality for you.
Sharp edges and small text show a faint halo at low JPEG quality. If you see it, raise the quality, or use WebP to PNG instead.
Names and extensions
Files are saved with a .jpg extension. Under File names in Advanced settings you can change the pattern, for example to {name}-{width}x{height}, which is handy when a form or a shop wants the size in the name. Names are lowercased with hyphens, which keeps them safe for upload fields that dislike spaces.
Colour
The browser converts colours to sRGB while it decodes the WebP, so the JPEG matches what you saw on screen. Metadata is removed by default. Open Advanced settings and look under Metadata if you want to keep the author line or the colour profile.
Questions
Why did my file get bigger?
JPEG compresses less efficiently than WebP. Lower the quality a little or use a size target if the result must stay small.
Can I turn the background black?
Yes. Pick any colour in the background setting.
Does it keep the original size in pixels?
Yes, unless you also choose a resize option.
Is the file uploaded?
No. The conversion runs on your device.