diff --git a/src/Http/Middleware/CheckRecaptcha.php b/src/Http/Middleware/CheckRecaptcha.php
index ead9c95..55a416b 100644
--- a/src/Http/Middleware/CheckRecaptcha.php
+++ b/src/Http/Middleware/CheckRecaptcha.php
@@ -101,7 +101,7 @@ protected function isPostMethod(Request $request)
     protected function hasValidRequest(Request $request)
     {
         $isValid = !$this->validator->make($request->only('_recaptcha'), [
-            '_recaptcha' => 'required|string|size:356',
+            '_recaptcha' => 'required|string|between:300,400',
         ])->fails();
 
         return throw_unless($isValid, InvalidRecaptchaException::class, $request->only('_recaptcha'));
diff --git a/tests/Middleware/CheckRecaptchaTest.php b/tests/Middleware/CheckRecaptchaTest.php
index f20037e..57575dc 100644
--- a/tests/Middleware/CheckRecaptchaTest.php
+++ b/tests/Middleware/CheckRecaptchaTest.php
@@ -86,7 +86,7 @@ public function testFailsOnNonPostMethod()
 
     public function testFailsInvalidToken()
     {
-        $response = $this->post('test-post', [ '_recaptcha' => Str::random(357)]);
+        $response = $this->post('test-post', [ '_recaptcha' => Str::random(401)]);
 
         $response->assertStatus(500);
         $this->assertInstanceOf(InvalidRecaptchaException::class, $response->exception);