diff --git a/src/__tests__/util.spec.ts b/src/__tests__/util.spec.ts
index 01de8b7f..8a5a25ca 100644
--- a/src/__tests__/util.spec.ts
+++ b/src/__tests__/util.spec.ts
@@ -59,6 +59,18 @@ describe("Hertz formatter", () => {
   it("supports megahertz", () => {
     expect(formatHertz(123.456e6)).toBe("123.456MHz");
   });
+
+  it("supports ronnahertz", () => {
+    expect(formatHertz(123.456e27)).toBe("123.456RHz");
+  });
+
+  it("falls back to exponential format for unreasonably large frequencies", () => {
+    expect(formatHertz(1.23456e40)).toBe("1.235e+40Hz");
+  });
+
+  it("zeros out with unreasonably small frequencies", () => {
+    expect(formatHertz(1.23456e-40)).toBe("0.000qHz");
+  });
 });
 
 describe("Auto key color algorithm", () => {
diff --git a/src/utils.ts b/src/utils.ts
index 98d77ef3..0cadfdc9 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -75,6 +75,12 @@ export function formatHertz(frequency: number, fractionDigits = 3) {
   }
 
   // Submultiples
+  if (magnitude < 1e-27) {
+    return (frequency * 1e30).toFixed(fractionDigits) + "qHz";
+  }
+  if (magnitude < 1e-24) {
+    return (frequency * 1e27).toFixed(fractionDigits) + "rHz";
+  }
   if (magnitude < 1e-21) {
     return (frequency * 1e24).toFixed(fractionDigits) + "yHz";
   }
@@ -101,11 +107,17 @@ export function formatHertz(frequency: number, fractionDigits = 3) {
   }
 
   // Too large. Use scientific notation.
-  if (magnitude > 1e28) {
+  if (magnitude > 1e34) {
     return formatExponential(frequency) + "Hz";
   }
 
   // Multiples
+  if (magnitude > 1e30) {
+    return (frequency * 1e-30).toFixed(fractionDigits) + "QHz";
+  }
+  if (magnitude > 1e27) {
+    return (frequency * 1e-27).toFixed(fractionDigits) + "RHz";
+  }
   if (magnitude > 1e24) {
     return (frequency * 1e-24).toFixed(fractionDigits) + "YHz";
   }