diff --git a/python/ray/dashboard/client/src/util/converter.ts b/python/ray/dashboard/client/src/util/converter.ts
index 0bfd52736de6..54d926b96688 100644
--- a/python/ray/dashboard/client/src/util/converter.ts
+++ b/python/ray/dashboard/client/src/util/converter.ts
@@ -1,4 +1,8 @@
-export const memoryConverter = (bytes: number) => {
+export const memoryConverter = (bytes: number | undefined | null) => {
+  if (typeof bytes !== "number" || Number.isNaN(bytes)) {
+    return "-";
+  }
+
   if (bytes < 1024) {
     return `${bytes.toFixed(4)}B`;
   }
diff --git a/python/ray/dashboard/client/src/util/converter.unit.test.ts b/python/ray/dashboard/client/src/util/converter.unit.test.ts
index a3d544c78d60..7adef830751c 100644
--- a/python/ray/dashboard/client/src/util/converter.unit.test.ts
+++ b/python/ray/dashboard/client/src/util/converter.unit.test.ts
@@ -37,4 +37,18 @@ describe("memoryConverter", () => {
   test.each(table)("$name", ({ input, expected }) => {
     expect(memoryConverter(input)).toEqual(expected);
   });
+
+  describe("edge cases", () => {
+    test("returns '-' for null", () => {
+      expect(memoryConverter(null)).toEqual("-");
+    });
+
+    test("returns '-' for undefined", () => {
+      expect(memoryConverter(undefined)).toEqual("-");
+    });
+
+    test("returns '-' for NaN", () => {
+      expect(memoryConverter(NaN)).toEqual("-");
+    });
+  });
 });