diff --git a/src/Modifiers/CoreModifiers.php b/src/Modifiers/CoreModifiers.php
index 15c2623de8..23b731b15e 100644
--- a/src/Modifiers/CoreModifiers.php
+++ b/src/Modifiers/CoreModifiers.php
@@ -1032,7 +1032,7 @@ public function isUppercase($value)
      */
     public function isUrl($value)
     {
-        return filter_var($value, FILTER_VALIDATE_URL) !== false;
+        return Str::isUrl($value);
     }
 
     /**
diff --git a/src/Support/Str.php b/src/Support/Str.php
index ebd68f274a..94378f2eca 100644
--- a/src/Support/Str.php
+++ b/src/Support/Str.php
@@ -115,7 +115,7 @@ public static function slugToTitle($string)
 
     public static function isUrl($string)
     {
-        return self::startsWith($string, ['http://', 'https://', '/']);
+        return self::startsWith($string, '/') || filter_var($string, FILTER_VALIDATE_URL) !== false;
     }
 
     public static function deslugify($string)
diff --git a/tests/Support/StrTest.php b/tests/Support/StrTest.php
index 0bf5d417b0..939c63f8c6 100644
--- a/tests/Support/StrTest.php
+++ b/tests/Support/StrTest.php
@@ -74,6 +74,8 @@ public function it_checks_for_a_url()
     {
         $this->assertTrue(Str::isUrl('http://example.com'));
         $this->assertTrue(Str::isUrl('https://example.com'));
+        $this->assertTrue(Str::isUrl('ftp://example.com'));
+        $this->assertTrue(Str::isUrl('mailto:bob@down.com'));
         $this->assertTrue(Str::isUrl('/relative'));
         $this->assertFalse(Str::isUrl('test'));
     }