Format Converter

JPG、PNG、WebP、AVIF間の変換。

Drop images here or click to upload

JPG, PNG, WebP · up to 50 images · 0/50 selected

Multi-format

Convert between JPG, PNG, WebP, AVIF.

Batch Convert

Convert multiple images at once.

ZIP Download

Download all converted files as ZIP.

Client-side

All processing in your browser. No data uploaded.

Format Converterについて

The Image Converter transforms your images between the most common web formats — JPEG, PNG, and WebP — entirely inside your browser. Different image formats suit different use cases: JPEG is ideal for photographs where small file size matters; PNG is best for graphics, logos, and images that need a transparent background; WebP is a modern format that delivers superior compression for both photographs and graphics and is supported by all major browsers. Converting between these formats is often necessary when a CMS or design tool only accepts one specific type, or when you want to optimise images for web delivery. This tool supports batch conversion of up to 50 images simultaneously, with a configurable quality slider for lossy formats. The output is ready to download immediately — individually or as a ZIP archive. Because processing runs client-side, conversion is instant and your files stay completely private.

Format Converterの使い方

  1. Drag and drop your images onto the upload zone, or click to browse — up to 50 files accepted at once.
  2. Choose the output format by clicking one of the format buttons: JPG, PNG, or WebP.
  3. For JPG and WebP, adjust the Quality slider to balance file size against visual fidelity.
  4. Conversion starts automatically. The new file size is displayed next to each image once ready.
  5. Click "Download" next to a single file to save it, or "Download all" to get a ZIP of all converted images.
  6. Switch between output formats at any time — all images will re-convert to the newly selected format.

よくある質問

Which format should I choose for my website?

WebP is the best choice for modern websites — it produces smaller files than both JPEG and PNG while maintaining quality. Use PNG when you need transparency, and JPEG for maximum compatibility with older systems.

Will converting PNG to JPEG remove the transparent background?

Yes. JPEG does not support transparency; transparent areas will be filled with white. Use WebP or keep the PNG format if you need to preserve alpha channels.

Does the quality slider affect PNG output?

No. PNG is a lossless format, so the quality slider is hidden when PNG is selected. The file will always be saved at full quality.

Are my images uploaded anywhere?

No. Conversion uses the browser's Canvas API entirely on your device. No data is sent to any server.

Can I convert animated GIFs?

The tool converts only the first frame of animated images. For animated GIF conversion, a dedicated animation tool is recommended.

Format Converterの完全ガイド：無料オンラインツール

ブラウザ完結で安全・高速なFormat Converter。開発者やクリエイターの作業を効率化

JPG、PNG、WebP、AVIF間の変換。を瞬時に実現する無料ツールです。面倒なソフトのインストールは不要で、安全にブラウザ上で処理できます。

Format Converterが選ばれる理由

  • 高速処理: ミリ秒単位で即時実行。
  • プライバシー保護: データは端末外に送信されません。
  • 完全無料: 登録不要で制限なく利用可能。

簡単な3つの利用手順

  1. Format Converterのページを開きます。
  2. データを入力または貼り付けます。
  3. 結果を確認してコピーまたは保存します。

機能比較

項目 Metoolzy Format Converter 他社オンラインツール 専用ソフト
料金 完全無料 制限あり 有料ライセンス
セキュリティ 完全ローカル処理 サーバー送信あり ローカル処理

主な活用シーン

  • エンジニアの開発・デバッグ効率化
  • Web制作者の日常作業
  • データ変換・最適化

よくある質問 (FAQ)

入力したデータは保存されますか？

いいえ、すべてブラウザ内で処理され保存されません。