MiniPNG

PNG to WebP Converter

Convert your PNG images to WebP online — free, fast, and transparency preserved.

100% 無料 安全・プライベート
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Convert PNG to WebP online, free

This is the one conversion here that does not ask you to give something up. A PNG with transparency has exactly one widely-supported destination that keeps it: WebP. Unlike JPG, WebP carries a real alpha channel, so logos, icons, stickers, UI screenshots, and any graphic with cut-out edges keep their transparency exactly as it was — while the file still comes back smaller than the PNG you uploaded.

Why a WebP beats a PNG on size

PNG's compression dates from the mid-1990s and stores images in a way that was clever then and is simply outclassed now. WebP's encoder describes the same pixels using fewer bytes, which is why a straightforward conversion usually produces a noticeably smaller file before you have made any other decision about it. For a site carrying dozens of PNG assets, that difference adds up quickly.

What this is best for

Flat graphics gain the most: logos, icons, illustrations, screenshots, and anything with large areas of solid colour and hard edges. Photographs stored as PNG — which were never a good fit for PNG in the first place — also shrink substantially. Either way, transparency in the source survives the conversion untouched.

Choosing a level

Fast, Recommended, and Smallest control how much effort goes into the encode. Recommended is the default and covers almost everything. Fast returns a large batch more quickly. Smallest works harder at reducing the file and is worth the extra time for assets that will be loaded on every page of a site.

Colour handling

Your colour profile is kept by default so nothing shifts. For assets going onto a website, Convert to sRGB is usually the better option — it makes the colours render identically in every browser rather than depending on how each one handles an unfamiliar profile.

Converting in bulk

Upload up to 100 PNGs at once from your device, Google Drive, or a direct URL. Original filenames are preserved, which matters when the files are referenced by name across a site or an app. Everything is deleted from the servers within an hour.

What you get

  • Transparency preserved exactly — no background colour substituted
  • A smaller file than the source PNG, usually noticeably so
  • Three levels covering speed, balance, and smallest output
  • Colour profile kept, or converted to sRGB for the web
  • Up to 100 files per batch with original filenames preserved
  • No account, no watermark, and files deleted within an hour

What's next?

Converting photographs as well? Convert JPG to WebP handles the JPG side of the same job. If a WebP file gets refused somewhere, Convert WebP to JPG converts it back. And if you need to keep the PNG format for compatibility, Compress PNG reduces the size without converting at all.

よくある質問

Yes, exactly as it was. WebP has a real alpha channel, the same as PNG, so nothing is composited onto a background colour — there is nothing that needs to be.

Almost always, and usually noticeably. PNG's compression is decades old; WebP describes the same image using fewer bytes. That gap is a large part of why the format was created.

Flat graphics — logos, icons, illustrations, and UI screenshots with large areas of solid colour. Photographs saved as PNG also shrink substantially, because PNG was never the right container for a photograph to begin with.

Transparency. WebP keeps your PNG's alpha channel intact; JPG cannot hold one at all, so transparent areas get filled with white. If the image has no transparency and you need the widest possible compatibility, JPG is a reasonable choice — otherwise WebP is the better one.

No. The colour profile is preserved by default. Choose Convert to sRGB instead if the asset is going onto a website and you want it to render identically across browsers.

Yes, up to 100 per batch from your device, Google Drive, or a direct URL, with original filenames kept.

PNG to WebP の使い方は簡単です。デバイス、Google Drive、または URL から最大 100 件のファイル(.png)をアップロードし、必要に応じて設定を調整して「PNG to WebP」ボタンをクリックするだけ。数秒で処理が完了し、すぐにダウンロードできます。

もちろんです。ファイルは暗号化された安全な接続(HTTPS)でアップロードされ、自動的に処理されます。誰もファイルを閲覧することはありません。すべてのファイルは1時間以内にサーバーから自動削除され、ゴミ箱アイコンからいつでも即座に手動削除もできます。

はい!PNG to WebP は完全無料です。登録もメールアドレスも不要で、隠れた費用もありません。ファイルをアップロードして結果をダウンロードするだけです。

ダウンロードやインストールは不要です。MiniPNG はブラウザ上で完全にオンラインで動作するため、Windows、Mac、Linux、Android、iOS などあらゆるデバイスで利用できます。

1ファイルあたり最大 200MB までアップロードできます。この制限により、すべてのユーザーに高速で安定した処理を提供しています。

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