diff --git a/Tests/convertTest.php b/Tests/convertTest.php
new file mode 100644
index 0000000..adcfd4c
--- /dev/null
+++ b/Tests/convertTest.php
@@ -0,0 +1,25 @@
+<?php
+
+require_once ("convert.php");
+
+/** Test the Conversion of format */
+class test_convert extends PHPUnit_Framework_TestCase
+{
+  public function test_convertDate1 ()
+  {
+    $res = \convert::convertDate ("2017-04-13", "Y-m-d", "d/m/Y");
+    $this->assertSame ($res, "13/04/2017");
+  }
+
+  public function test_convertDate2 ()
+  {
+    $this->setExpectedException ("Exception");
+    $res = \convert::convertDate ("2017-13-33", "Y-m-d", "d/m/Y", true);
+  }
+
+  public function test_convertDate3 ()
+  {
+    $res = \convert::convertDate ("2017-13-33", "Y-m-d", "d/m/Y");
+    $this->assertSame ($res, "2017-13-33");
+  }
+}
diff --git a/convert.php b/convert.php
new file mode 100644
index 0000000..f01f8f6
--- /dev/null
+++ b/convert.php
@@ -0,0 +1,43 @@
+<?php
+/** DomFramework
+    @package domframework
+    @author Dominique Fournier <dominique@fournier38.fr> */
+
+/** Convert a format to another one
+  */
+class convert
+{
+  /** Convert Date received in one format to another.
+    * If the provided string is not corresponding to the format, don't change
+    * anything.
+    * Format used http://php.net/manual/en/datetime.createfromformat.php
+    * Do not accept the locale ! The language of the dates is always in english
+    * @param string $inputDate The date to modify
+    * @param string $inputFormat The input format of the date
+    * @param string $outputFormat The output format of the date
+    * @param bool|null $exception If set, generate an exception if the provided
+    * date is invalid
+    * @return string
+    */
+  public static function convertDate ($inputDate, $inputFormat, $outputFormat,
+                                      $exception = false)
+  {
+    $date = \DateTime::CreateFromFormat ($inputFormat, $inputDate);
+    if ($date === false)
+    {
+      if ($exception !== false)
+        throw new \Exception (
+          "Invalid date provided or not matching the format", 500);
+      return $inputDate;
+    }
+    $errors = $date->getLastErrors();
+    if ($errors["warning_count"] > 0 || $errors["error_count"] > 0)
+    {
+      if ($exception !== false)
+        throw new \Exception (
+          "Invalid date provided or not matching the format", 500);
+      return $inputDate;
+    }
+    return $date->format ($outputFormat);
+  }
+}