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MIME タイプの確認

ファイルの MIME タイプを確認

ブラウザで動作 · アップロード不要

このツールとページ内の説明は、現在は英語のみです。動作は同じで、すべてブラウザ内で実行されます。

Drag & drop files here

or

Any file type, one or many. Only the start of each file is read.

Your files stay on your device. Nothing is uploaded.

  • 何も端末から出ません
  • サーバーによるサイズ制限なし
  • 登録不要・透かしなし
  • 無料

How to check a MIME type

  1. Choose one or more files.
  2. Compare the MIME type detected from the contents with the one expected from the file name and the one reported by your browser.
  3. Fix the extension if they don't match.

Three answers, and why they differ

  • From contents: read from the file's own signature. This is what the file really is.
  • From the file name: what the extension normally means.
  • Reported by your browser: usually based only on the extension and your operating system's settings, and sometimes empty.

Is my file uploaded?

No. Your file is processed locally in your browser and never leaves your device. This site has no upload feature, and its security policy blocks the page from uploading anything.

よくある質問

Why does a website reject my file?

Many sites check the real content type. If a file is named .jpg but contains WebP or HEIC data, it can be rejected. Convert it to the expected format.

Is my file uploaded?

No. Only the start of the file is read, in your browser.