diff --git a/Base/res/js/Spreadsheet/runtime.js b/Base/res/js/Spreadsheet/runtime.js
index 92b003729c..d34b3e3ffe 100644
--- a/Base/res/js/Spreadsheet/runtime.js
+++ b/Base/res/js/Spreadsheet/runtime.js
@@ -365,6 +365,9 @@ function randRange(min, max) {
 }
 
 function integer(value) {
+    const typeVal = typeof value;
+    if ((typeVal !== "number" && typeVal !== "string") || Number.isNaN(Number(value)))
+        throw new Error(`integer() called with unexpected type "${typeVal}"`);
     return value | 0;
 }
 
@@ -381,7 +384,7 @@ function numericReduce(op, accumulator, cells) {
 }
 
 function numericResolve(cells) {
-    return resolve(cells).map(str => (str === "" || str == null ? NaN : integer(str)));
+    return resolve(cells).map(val => parseInt(val));
 }
 
 function resolve(cells) {
diff --git a/Userland/Applications/Spreadsheet/Tests/free-functions.js b/Userland/Applications/Spreadsheet/Tests/free-functions.js
index dc142d0bd3..9a55046075 100644
--- a/Userland/Applications/Spreadsheet/Tests/free-functions.js
+++ b/Userland/Applications/Spreadsheet/Tests/free-functions.js
@@ -203,3 +203,36 @@ describe("Lookup", () => {
         expect(reflookup("80", R`A0:A9`, R`B0:B9`, undefined, "nextlargest").name).toEqual("B9");
     });
 });
+
+describe("integer() function", () => {
+    test("undefined", () => {
+        expect(() => integer(undefined)).toThrow(Error);
+    });
+    test("null", () => {
+        expect(() => integer(null)).toThrow(Error);
+    });
+    test("NaN", () => {
+        expect(() => integer(NaN)).toThrow(Error);
+    });
+    test("object", () => {
+        expect(() => integer({})).toThrow(Error);
+    });
+    test("function", () => {
+        expect(() => integer(() => {})).toThrow(Error);
+    });
+    test("try 1 as string", () => {
+        expect(integer("1")).toBe(1);
+    });
+    test("try 1 as number", () => {
+        expect(integer(1)).toBe(1);
+    });
+    test("try 1000000 as string", () => {
+        expect(integer("1000000")).toBe(1000000);
+    });
+    test("try 1000000 as number", () => {
+        expect(integer(1000000)).toBe(1000000);
+    });
+    test("don't just allow any strings", () => {
+        expect(() => integer("is this NaN yet?")).toThrow();
+    });
+});