diff --git a/spec/loophp/Tin/CountryHandler/SlovakiaSpec.php b/spec/loophp/Tin/CountryHandler/SlovakiaSpec.php
index 8b73c66..23735cb 100644
--- a/spec/loophp/Tin/CountryHandler/SlovakiaSpec.php
+++ b/spec/loophp/Tin/CountryHandler/SlovakiaSpec.php
@@ -15,7 +15,11 @@ class SlovakiaSpec extends AbstractAlgorithmSpec
 {
     public const INVALID_NUMBER_LENGTH = '77111674201';
 
+    public const INVALID_SYNTAX = '2812030541';
+
     public const VALID_NUMBER = '7711167420';
 
     public const VALID_NUMBER2 = '281203054';
+
+    public const VALID_NUMBER3 = '2822030541';
 }
diff --git a/src/CountryHandler/Slovakia.php b/src/CountryHandler/Slovakia.php
index 1532b34..50a4daf 100644
--- a/src/CountryHandler/Slovakia.php
+++ b/src/CountryHandler/Slovakia.php
@@ -9,6 +9,8 @@
 
 namespace loophp\Tin\CountryHandler;
 
+use function strlen;
+
 /**
  * Slovakia.
  */
@@ -24,12 +26,27 @@ final class Slovakia extends CountryHandler
      */
     public const LENGTH = 10;
 
+    public const PATTERN = '([1-9]\\d[234789]\\d{7})|(\\d{2}[0156]\\d[0-3]\\d{4,5})';
+
+    public function hasValidRule(string $tin): bool
+    {
+        if (strlen($tin) === 10) {
+            if ((int) $tin % 11 === 0) {
+                return true;
+            }
+
+            return (int) substr($tin, 9, 1) === ((int) substr($tin, 0, 9) % 11) % 10;
+        }
+
+        return true;
+    }
+
     protected function hasValidLength(string $tin): bool
     {
         $c1c2 = substr($tin, 0, 2);
 
         if (54 > $c1c2) {
-            return $this->matchLength($tin, self::LENGTH - 1);
+            return $this->matchLength($tin, self::LENGTH) || $this->matchLength($tin, self::LENGTH - 1);
         }
 
         return parent::hasValidLength($tin);