diff --git a/src/Validator/StringLengthBetween.php b/src/Validator/StringLengthBetween.php
index d0df507..3b89b0d 100644
--- a/src/Validator/StringLengthBetween.php
+++ b/src/Validator/StringLengthBetween.php
@@ -15,11 +15,10 @@ protected function describe()
      */
     protected function parse($value)
     {
-        if (!is_string($value)) {
-            return null;
+        if (strlen($value) >= $this->minValue && strlen($value) <= $this->maxValue) {
+            return $value;
         }
-        $value = strlen($value);
-        return parent::parse($value);
+        return null;
     }
 
     /**
diff --git a/src/Validator/StringLengthLargerThanOrEqualToParser.php b/src/Validator/StringLengthLargerThanOrEqualToParser.php
index 112e5ec..e170eab 100644
--- a/src/Validator/StringLengthLargerThanOrEqualToParser.php
+++ b/src/Validator/StringLengthLargerThanOrEqualToParser.php
@@ -15,11 +15,10 @@ protected function describe()
      */
     protected function parse($value)
     {
-        if (!is_string($value)) {
-            return null;
+        if (strlen($value) >= $this->minValue) {
+            return $value;
         }
-        $value = strlen($value);
-        return parent::parse($value);
+        return null;
     }
 
     /**
diff --git a/src/Validator/StringLengthLargerThanParser.php b/src/Validator/StringLengthLargerThanParser.php
index eb4b1a7..04c46ef 100644
--- a/src/Validator/StringLengthLargerThanParser.php
+++ b/src/Validator/StringLengthLargerThanParser.php
@@ -15,11 +15,10 @@ protected function describe()
      */
     protected function parse($value)
     {
-        if (!is_string($value)) {
-            return null;
+        if (strlen($value) > $this->minValue) {
+            return $value;
         }
-        $value = strlen($value);
-        return parent::parse($value);
+        return null;
     }
 
     /**
diff --git a/src/Validator/StringLengthSmallerThanOrEqualToParser.php b/src/Validator/StringLengthSmallerThanOrEqualToParser.php
index 32143cb..f187878 100644
--- a/src/Validator/StringLengthSmallerThanOrEqualToParser.php
+++ b/src/Validator/StringLengthSmallerThanOrEqualToParser.php
@@ -15,11 +15,10 @@ protected function describe()
      */
     protected function parse($value)
     {
-        if (!is_string($value)) {
-            return null;
+        if (strlen($value) <= $this->maxValue) {
+            return $value;
         }
-        $value = strlen($value);
-        return parent::parse($value);
+        return null;
     }
 
     /**
diff --git a/src/Validator/StringLengthSmallerThanParser.php b/src/Validator/StringLengthSmallerThanParser.php
index d2d0691..3f948ff 100644
--- a/src/Validator/StringLengthSmallerThanParser.php
+++ b/src/Validator/StringLengthSmallerThanParser.php
@@ -15,11 +15,10 @@ protected function describe()
      */
     protected function parse($value)
     {
-        if (!is_string($value)) {
-            return null;
+        if (strlen($value) < $this->maxValue) {
+            return $value;
         }
-        $value = strlen($value);
-        return parent::parse($value);
+        return null;
     }
 
     /**