diff --git a/src/Core/Convert.php b/src/Core/Convert.php
index 45b8d4df9..1642f9abb 100644
--- a/src/Core/Convert.php
+++ b/src/Core/Convert.php
@@ -553,6 +553,7 @@ class Convert
 
     /**
      * Turn a memory string, such as 512M into an actual number of bytes.
+     * Preserves integer values like "1024" or "-1"
      *
      * @param string $memString A memory limit string, such as "64M"
      * @return float
@@ -562,7 +563,7 @@ class Convert
         // Remove  non-unit characters from the size
         $unit = preg_replace('/[^bkmgtpezy]/i', '', $memString);
         // Remove non-numeric characters from the size
-        $size = preg_replace('/[^0-9\.]/', '', $memString);
+        $size = preg_replace('/[^0-9\.\-]/', '', $memString);
 
         if ($unit) {
             // Find the position of the unit in the ordered string which is the power
diff --git a/tests/php/Core/ConvertTest.php b/tests/php/Core/ConvertTest.php
index f435e1eb0..af8d454c1 100644
--- a/tests/php/Core/ConvertTest.php
+++ b/tests/php/Core/ConvertTest.php
@@ -576,6 +576,7 @@ XML
     public function memString2BytesProvider()
     {
         return [
+            ['-1', (float)-1],
             ['2048', (float)(2 * 1024)],
             ['2k', (float)(2 * 1024)],
             ['512M', (float)(512 * 1024 * 1024)],