Kilomill

Kilomill JPG to WebP

Convert JPG to WebP

WebP makes website images smaller than JPG at the same visual quality, which helps pages load faster and improves Core Web Vitals. Convert a whole folder here with Google’s libwebp encoder.

  • No upload: runs in your browser
  • Batch + ZIP download
  • No sign-up, no watermark

Drop JPG images here

or paste from the clipboard · JPG, PNG, WebP, AVIF, HEIC, GIF, BMP · no upload

Output format
File size

For JPG, WebP and AVIF. 70–80 is hard to tell from the original. PNG uses smart colour reduction instead (see Advanced).

KB
KB

Aims at or below the maximum counting 1 KB = 1,000 bytes, so the file passes whether a site counts 1,000 or 1,024 bytes per KB.

Dimensions

Leave one box empty to keep the proportions.

%
px
Advanced
PNG output
dpi

Metadata (EXIF, GPS location, camera details) is removed from every output file.

Settings for website images

ImageSuggested settings
Large photo (hero, banner)Quality 75–80; Longest side 1600–2400 px
Content photo, product photoQuality 75–80; width matching your layout, ×2 for high-DPI screens
ThumbnailQuality 70; Width × height with “Fill exactly (crop the edges)”
Logo or graphic with transparencyStart from the PNG and use PNG to WebP

Using WebP on a website

All current major browsers display WebP. If you also need to support very old browsers or email clients, serve WebP with a JPG fallback using the HTML <picture> element:

<picture>
  <source srcset="photo.webp" type="image/webp">
  <img src="photo.jpg" alt="…" width="1200" height="800">
</picture>

For even smaller files, try AVIF (choose it under Output format); it takes longer to encode.

Questions and answers

How much smaller is WebP than JPG?

It depends on the image. Google’s WebP documentation reports lossy WebP files 25–34% smaller than comparable JPEG images at equivalent quality in its study; your own results are shown for every file.

Will WebP images work in email?

Not reliably. Many email clients don’t display WebP, so use JPG for newsletters.

Should I use WebP or AVIF?

AVIF is usually smaller still but slower to encode and less widely supported outside browsers. WebP is the safe default; AVIF is worth it for large, frequently viewed images.

Are my images uploaded to a server?

No. The images are read and compressed by code running in this browser tab, and the results are created in your device’s memory. Nothing is sent anywhere, which you can confirm in your browser’s developer tools (Network tab) while you work. See Privacy.

Related tools

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Crop & rotate

Image to crop