Convert JPG to WebP
Cut image weight by 25–35% at the same visual quality — the single easiest page-speed win.
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対応形式: JPG
ローカルで処理します。画像が端末の外に出ることはありません。
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WebP was designed to replace JPEG on the web, and at equivalent visual quality it usually lands 25–35% smaller. On an image-heavy page that is the difference between a fast Largest Contentful Paint and a slow one.
Support is no longer a concern: every current browser reads WebP. The remaining caveat is outside the browser — some desktop applications and older email clients still do not, so WebP is a format for shipping to the web, not for archiving.
できること
Meaningfully smaller files
Typically a quarter to a third off, with no visible quality difference at normal viewing size.
Better Core Web Vitals
Smaller images download faster, which directly improves Largest Contentful Paint.
Quality slider included
Tune the trade-off yourself instead of accepting one preset.
No upload
Your browser has a WebP encoder built in. The conversion uses it locally.
使い方
- 1
Load the JPG
Decoded locally by the browser.
- 2
Choose a quality
75–85 is the usual range for photographs on the web.
- 3
Download the WebP
Encoded in-browser and saved straight to your device.
KaiConvert を選ぶ理由
- ローカルツールはアップロード不要
- ページ読み込み後はオフラインでも動作
- クラウド AI は開始前に必ず明示