diff --git a/src/validation/rules.ts b/src/validation/rules.ts
index 3ee278b..fff2b79 100644
--- a/src/validation/rules.ts
+++ b/src/validation/rules.ts
@@ -165,7 +165,7 @@ const rules: Record<string, ValidationRuleFn> = {
         }
 
         if (typeof value === 'string' || (force === 'length')) {
-            value = !isNaN(value) ? value.toString() : value
+            value = !isNaN(value) ? String(value) : value
             return value.length <= maximum
         }
 
@@ -187,7 +187,7 @@ const rules: Record<string, ValidationRuleFn> = {
         }
 
         if (typeof value === 'string' || (force === 'length')) {
-            value = !isNaN(value) ? value.toString() : value
+            value = !isNaN(value) ? String(value) : value
             return value.length >= minimum
         }