コード識別
音符を選択してコードを識別 — ピアノまたはテキスト入力対応
コードを識別するには2つ以上の音符を選択してください
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使い方
ツールを開く
セットアップ不要 — ツールはブラウザで即座に読み込まれます。
操作して探索
マウス、キーボード、またはタッチでリアルタイムに操作します。
いつでもどこでも利用可能
デスクトップとモバイルに対応 — 外出先でも練習や作成ができます。
このツールを使う理由
完全無料
隠れたコストもプレミアムプランもありません — すべての機能が無料です。
インストール不要
すべてブラウザで実行されます。ソフトウェアのダウンロードやインストールは不要です。
プライベート＆安全
データはデバイスの外に出ることはありません。サーバーにアップロードされることはありません。
モバイル対応
完全レスポンシブ対応 — スマートフォン、タブレット、デスクトップで利用できます。
How Chord Identification Works
Key Takeaways
- Chords are built by stacking intervals — the specific combination determines the chord quality (major, minor, diminished, etc.).
- The same notes can be named differently depending on which note is the root (inversions).
- This tool uses the tonal.js library to detect all possible chord names from your selected notes.
Chord identification determines a chord's name and quality from a set of notes. Whether you are transcribing by ear, analyzing a score, or experimenting with voicings, knowing what chord you are playing unlocks deeper musical understanding. This tool analyzes your selected notes and returns all matching chord names.
50+
Chord qualities recognized
Core Concepts
Triads: The Building Blocks
A triad is a three-note chord: root, third, and fifth. Major triads use major third + minor third (C–E–G). Minor triads reverse: minor third + major third (C–Eb–G).
Seventh Chords
Adding a note a third above the fifth creates seventh chords. Types include major 7th (Cmaj7), dominant 7th (C7), minor 7th (Cm7), and half-diminished (Cm7b5).
Inversions & Voicings
When a note other than the root is in the bass, the chord is inverted. C/E (1st inversion) and C/G (2nd inversion) contain the same notes but sound distinctly different.
Extended & Altered Chords
Jazz and contemporary music use 9th, 11th, and 13th chords. Altered chords modify the 5th or 9th with sharps or flats for added tension.
Tips for Chord Identification
Start by identifying the root — usually the lowest note or the one that sounds most stable.
Count semitones between notes: root to major third is 4, root to minor third is 3.
If multiple names are returned, consider musical context — the chord fitting the key is usually correct.
Use the piano input to click notes, or type note names directly (e.g. C E G Bb) for quick identification.
All chord analysis is performed locally in your browser using the tonal.js library. No note data is sent to any server.