diff --git a/robs_metronome.html b/robs_metronome.html
index 5e1c50c..66cf287 100644
--- a/robs_metronome.html
+++ b/robs_metronome.html
@@ -263,6 +263,55 @@
         margin-top: 10px;
         min-height: 1em;
       }
+
+      .tuner-grid {
+        display: grid;
+        grid-template-columns: repeat(6, 1fr);
+        gap: 8px;
+      }
+      .string-btn {
+        display: flex;
+        flex-direction: column;
+        align-items: center;
+        gap: 2px;
+        background: var(--panel);
+        border: 1px solid var(--rule);
+        border-radius: 6px;
+        padding: 12px 4px;
+        cursor: pointer;
+        font-family: "Work Sans";
+        color: var(--ink);
+        transition:
+          background 0.12s ease,
+          border-color 0.12s ease;
+      }
+      .string-btn .note {
+        font-family: "Fraunces", serif;
+        font-size: 1.3rem;
+        font-weight: 600;
+        color: var(--walnut);
+      }
+      .string-btn .hz {
+        font-size: 0.68rem;
+        color: var(--ink-soft);
+        font-variant-numeric: tabular-nums;
+      }
+      .string-btn:hover {
+        border-color: var(--brass);
+      }
+      .string-btn.active {
+        background: var(--brass-light);
+        border-color: var(--brass);
+      }
+      .string-btn.active .note {
+        color: var(--walnut);
+      }
+      .tuner-hint {
+        text-align: center;
+        font-size: 0.8rem;
+        color: var(--ink-soft);
+        margin-top: 12px;
+      }
     </style>
   </head>
   <body>
@@ -304,6 +353,14 @@
 
       <hr class="divider" />
 
+      <h2>Tuner</h2>
+      <div class="tuner-grid" id="tunerGrid"></div>
+      <p class="tuner-hint">
+        Tap a string to play its tone. Tap again to stop.
+      </p>
+
+      <hr class="divider" />
+
       <h2>Your tunes</h2>
       <div class="tune-list" id="tuneList">
         <div class="empty" id="emptyMsg">Loading…</div>
@@ -330,10 +387,8 @@
           accept="application/json"
           style="display: none"
         />
-        <a href="https://tuner-online.com/#sounds" target="_blank">
-          <button>Guitar Tuner</button>
-        </a>
       </div>
+
       <div class="status" id="statusMsg"></div>
     </div>
 
@@ -455,6 +510,79 @@
         flashPad(false);
       });
 
+      // ---------- Guitar tuner ----------
+      const GUITAR_STRINGS = [
+        { note: "E", octave: 2, freq: 82.41 },
+        { note: "A", octave: 2, freq: 110.0 },
+        { note: "D", octave: 3, freq: 146.83 },
+        { note: "G", octave: 3, freq: 196.0 },
+        { note: "B", octave: 3, freq: 246.94 },
+        { note: "E", octave: 4, freq: 329.63 },
+      ];
+
+      const tunerGrid = document.getElementById("tunerGrid");
+      let tuneOsc = null;
+      let tuneGain = null;
+      let activeStringBtn = null;
+
+      function stopTunerTone() {
+        if (tuneOsc) {
+          const g = tuneGain;
+          const now = audioCtx.currentTime;
+          g.gain.cancelScheduledValues(now);
+          g.gain.setValueAtTime(g.gain.value, now);
+          g.gain.exponentialRampToValueAtTime(0.0001, now + 0.06);
+          tuneOsc.stop(now + 0.08);
+        }
+        if (activeStringBtn) activeStringBtn.classList.remove("active");
+        tuneOsc = null;
+        tuneGain = null;
+        activeStringBtn = null;
+      }
+
+      function playTunerTone(freq, btn) {
+        ensureAudio();
+        if (audioCtx.state === "suspended") audioCtx.resume();
+
+        // Toggle off if this string is already sounding
+        if (activeStringBtn === btn) {
+          stopTunerTone();
+          return;
+        }
+
+        stopTunerTone();
+
+        const osc = audioCtx.createOscillator();
+        const gain = audioCtx.createGain();
+        osc.type = "sine";
+        osc.frequency.value = freq;
+        const now = audioCtx.currentTime;
+        gain.gain.setValueAtTime(0.0001, now);
+        gain.gain.exponentialRampToValueAtTime(0.28, now + 0.03);
+        osc.connect(gain);
+        gain.connect(audioCtx.destination);
+        osc.start();
+
+        tuneOsc = osc;
+        tuneGain = gain;
+        activeStringBtn = btn;
+        btn.classList.add("active");
+      }
+
+      GUITAR_STRINGS.forEach((s) => {
+        const btn = document.createElement("button");
+        btn.className = "string-btn";
+        btn.innerHTML =
+          '<span class="note">' +
+          s.note +
+          s.octave +
+          '</span><span class="hz">' +
+          s.freq.toFixed(2) +
+          " Hz</span>";
+        btn.addEventListener("click", () => playTunerTone(s.freq, btn));
+        tunerGrid.appendChild(btn);
+      });
+
       // ---------- Tune storage (browser-local cache + JSON export/import) ----------
       const tuneList = document.getElementById("tuneList");
       const emptyMsg = document.getElementById("emptyMsg");