diff --git a/htdocs/core/modules/expedition/doc/pdf_rouget.modules.php b/htdocs/core/modules/expedition/doc/pdf_rouget.modules.php
index 76c2a1a93b1..3b440ea9615 100644
--- a/htdocs/core/modules/expedition/doc/pdf_rouget.modules.php
+++ b/htdocs/core/modules/expedition/doc/pdf_rouget.modules.php
@@ -694,8 +694,8 @@ class pdf_rouget extends ModelePdfExpedition
 		$totalToShip = $tmparray['toship'];
 		// Set trueVolume and volume_units not currently stored into database
 		if ($object->trueWidth && $object->trueHeight && $object->trueDepth) {
-			$object->trueVolume = price(($object->trueWidth * $object->trueHeight * $object->trueDepth), 0, $outputlangs, 0, 0);
-			$object->volume_units = $object->size_units * 3;
+			$object->trueVolume = price(((float) $object->trueWidth * (float) $object->trueHeight * (float) $object->trueDepth), 0, $outputlangs, 0, 0);
+			$object->volume_units = (float) $object->size_units * 3;
 		}
 
 		if ($totalWeight != '') {