diff --git a/packages/dial-slider/src/utils/dial-slider/ring-math.ts b/packages/dial-slider/src/utils/dial-slider/ring-math.ts
index 837687d..d61755d 100644
--- a/packages/dial-slider/src/utils/dial-slider/ring-math.ts
+++ b/packages/dial-slider/src/utils/dial-slider/ring-math.ts
@@ -3,7 +3,10 @@ interface Point {
   y: number;
 }
 
-/** Bipolar fill: + side vs maxValue, − side vs |minValue|. */
+/**
+ * Progress away from the neutral value. Neutral is zero when it is in range,
+ * otherwise the nearest range boundary.
+ */
 export function getBipolarProgress(
   value: number,
   minValue: number,
@@ -20,12 +23,18 @@ export function getBipolarProgress(
   const min = Math.min(minValue, maxValue);
   const max = Math.max(minValue, maxValue);
   const clampedValue = Math.min(max, Math.max(min, value));
-  if (clampedValue >= 0) {
-    return max <= 0 ? 0 : Math.min(Math.max(clampedValue / max, 0), 1);
+  const neutral = Math.min(max, Math.max(min, 0));
+
+  if (clampedValue >= neutral) {
+    const positiveRange = max - neutral;
+    return positiveRange <= 0
+      ? 0
+      : Math.min(Math.max((clampedValue - neutral) / positiveRange, 0), 1);
   }
-  return min >= 0
+  const negativeRange = neutral - min;
+  return negativeRange <= 0
     ? 0
-    : Math.min(Math.max(Math.abs(clampedValue) / Math.abs(min), 0), 1);
+    : Math.min(Math.max((neutral - clampedValue) / negativeRange, 0), 1);
 }
 
 export function getSignedProgressColor(
diff --git a/packages/dial-slider/tests/ring-math.test.ts b/packages/dial-slider/tests/ring-math.test.ts
index 9e823c5..81f9dd5 100644
--- a/packages/dial-slider/tests/ring-math.test.ts
+++ b/packages/dial-slider/tests/ring-math.test.ts
@@ -13,6 +13,16 @@ describe('preset progress ring', () => {
     expect(getBipolarProgress(0, -100, 100)).toBe(0);
   });
 
+  test('starts one-sided ranges at their nearest-to-zero boundary', () => {
+    expect(getBipolarProgress(10, 10, 20)).toBe(0);
+    expect(getBipolarProgress(15, 10, 20)).toBe(0.5);
+    expect(getBipolarProgress(20, 10, 20)).toBe(1);
+
+    expect(getBipolarProgress(-10, -20, -10)).toBe(0);
+    expect(getBipolarProgress(-15, -20, -10)).toBe(0.5);
+    expect(getBipolarProgress(-20, -20, -10)).toBe(1);
+  });
+
   test('clamps progress and safely rejects non-finite configuration', () => {
     expect(getBipolarProgress(500, -100, 100)).toBe(1);
     expect(getBipolarProgress(-500, -100, 100)).toBe(1);