diff --git a/src/tools/integer-base-converter/integer-base-converter.model.test.ts b/src/tools/integer-base-converter/integer-base-converter.model.test.ts
index d0387b64..c7d7db79 100644
--- a/src/tools/integer-base-converter/integer-base-converter.model.test.ts
+++ b/src/tools/integer-base-converter/integer-base-converter.model.test.ts
@@ -11,6 +11,9 @@ describe('integer-base-converter', () => {
         expect(convertBase({ value: '10100101', fromBase: 2, toBase: 16 })).toEqual('a5');
         expect(convertBase({ value: '192654', fromBase: 10, toBase: 8 })).toEqual('570216');
         expect(convertBase({ value: 'zz', fromBase: 64, toBase: 10 })).toEqual('2275');
+        expect(convertBase({ value: '42540766411283223938465490632011909384', fromBase: 10, toBase: 10 })).toEqual('42540766411283223938465490632011909384');
+        expect(convertBase({ value: '42540766411283223938465490632011909384', fromBase: 10, toBase: 16 })).toEqual('20010db8000085a300000000ac1f8908');
+        expect(convertBase({ value: '20010db8000085a300000000ac1f8908', fromBase: 16, toBase: 10 })).toEqual('42540766411283223938465490632011909384');
       });
     });
   });
diff --git a/src/tools/integer-base-converter/integer-base-converter.model.ts b/src/tools/integer-base-converter/integer-base-converter.model.ts
index b4470e57..da0fe77f 100644
--- a/src/tools/integer-base-converter/integer-base-converter.model.ts
+++ b/src/tools/integer-base-converter/integer-base-converter.model.ts
@@ -5,16 +5,16 @@ export function convertBase({ value, fromBase, toBase }: { value: string; fromBa
   let decValue = value
     .split('')
     .reverse()
-    .reduce((carry: number, digit: string, index: number) => {
+    .reduce((carry: bigint, digit: string, index: number) => {
       if (!fromRange.includes(digit)) {
         throw new Error(`Invalid digit "${digit}" for base ${fromBase}.`);
       }
-      return (carry += fromRange.indexOf(digit) * fromBase ** index);
-    }, 0);
+      return (carry += BigInt(fromRange.indexOf(digit)) * BigInt(fromBase) ** BigInt(index));
+    }, 0n);
   let newValue = '';
   while (decValue > 0) {
-    newValue = toRange[decValue % toBase] + newValue;
-    decValue = (decValue - (decValue % toBase)) / toBase;
+    newValue = toRange[Number(decValue % BigInt(toBase))] + newValue;
+    decValue = (decValue - (decValue % BigInt(toBase))) / BigInt(toBase);
   }
   return newValue || '0';
 }