diff --git a/modules/spl-meter/client.js b/modules/spl-meter/client.js
index 85909ee..59e3765 100644
--- a/modules/spl-meter/client.js
+++ b/modules/spl-meter/client.js
@@ -196,6 +196,38 @@ function readoutView(root, moduleApi) {
   const unit = root.querySelector('.spl-unit');
   const sub = root.querySelector('.spl-sub');
   const box = root.querySelector('.spl-readout');
+  const value = root.querySelector('.spl-value');
+  let fitKey = '';
+
+  /**
+   * Grow the number until it fills the tile, measuring the text we actually
+   * have rather than assuming a digit count.
+   *
+   * The CSS can only guess at width — it has to pick a cqw coefficient for
+   * some number of characters, and then "-100.5" overflows the tile that
+   * "-45.9" merely filled. Measuring costs one layout read, and only when
+   * the tile size or the length of the reading changes.
+   */
+  function fit() {
+    const w = root.clientWidth, h = root.clientHeight;
+    const key = `${w}x${h}:${num.textContent.length}:${unit.textContent}`;
+    if (key === fitKey || w < 2 || h < 2) return;
+    fitKey = key;
+
+    const TRIAL = 100;
+    num.style.fontSize = `${TRIAL}px`;
+    unit.style.fontSize = `${TRIAL * 0.26}px`;
+    const natural = value.scrollWidth || 1;
+
+    // Leave the caption its room when it is showing, and a little air either
+    // way so descenders and the tile's padding never clip.
+    const subH = sub.offsetParent ? sub.getBoundingClientRect().height + 6 : 0;
+    const byHeight = (h - subH) * 0.92;
+    const byWidth = ((w - 8) * TRIAL) / natural;
+    const size = Math.max(12, Math.min(byHeight, byWidth));
+    num.style.fontSize = `${size}px`;
+    unit.style.fontSize = `${size * 0.26}px`;
+  }
 
   return {
     render(payload) {
@@ -205,6 +237,7 @@ function readoutView(root, moduleApi) {
         num.textContent = '––.–';
         sub.textContent = payload && payload.error ? payload.error : '';
         box.dataset.level = 'idle';
+        fit();
         return;
       }
       const value = readValue(ch, s);
@@ -225,8 +258,9 @@ function readoutView(root, moduleApi) {
       if (ch.clip) parts.push('CLIP');
       if (!payload.calibrated) parts.push('uncalibrated');
       sub.textContent = parts.join('  ·  ');
+      fit();
     },
-    resize() {},
+    resize() { fitKey = ''; fit(); },
     destroy() { root.innerHTML = ''; },
   };
 }
diff --git a/modules/spl-meter/module.json b/modules/spl-meter/module.json
index 7a5eb03..f35af77 100644
--- a/modules/spl-meter/module.json
+++ b/modules/spl-meter/module.json
@@ -1,7 +1,7 @@
 {
   "id": "spl-meter",
   "name": "SPL Meter",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "proddash": ">=1.5.0",
   "description": "Calibrated sound level, Leq and RTA from an audio input on this machine",
   "permissions": [
diff --git a/modules/spl-meter/style.css b/modules/spl-meter/style.css
index 98e2dda..a120f46 100644
--- a/modules/spl-meter/style.css
+++ b/modules/spl-meter/style.css
@@ -30,18 +30,19 @@
   color: var(--text);
 }
 
-/* Sized off the tile, so one cell and six cells both read well. Height has
-   to be in the min() as well as width: a 2x1 tile is wide and short, and
-   sizing on width alone pushes the digits straight out through the top. */
+/* A first-paint size only. client.js measures the text and sets the real
+   one inline, because CSS has to assume a digit count and gets it wrong the
+   moment the reading needs a sixth character: the coefficient that fills a
+   tile for "-45.9" pushes "-100.5" straight out through the side. */
 [data-module="spl-meter"] .spl-num {
-  font-size: clamp(1.25rem, min(20cqw, 42cqh), 6rem);
+  font-size: clamp(1.25rem, min(26cqw, 60cqh), 100rem);
   font-variant-numeric: tabular-nums;
   font-weight: 600;
   letter-spacing: -0.02em;
 }
 
 [data-module="spl-meter"] .spl-unit {
-  font-size: clamp(0.65rem, min(6cqw, 13cqh), 1.5rem);
+  font-size: clamp(0.65rem, min(7cqw, 15cqh), 26rem);
   color: var(--muted);
 }