diff --git a/addons/web_editor/static/src/js/common/utils.js b/addons/web_editor/static/src/js/common/utils.js
index c05e7a2064e..2608bafedbf 100644
--- a/addons/web_editor/static/src/js/common/utils.js
+++ b/addons/web_editor/static/src/js/common/utils.js
@@ -102,7 +102,7 @@ function _convertNumericToUnit(value, unitFrom, unitTo, cssProp, $target) {
  * @returns {Array|null}
  */
 function _getNumericAndUnit(value) {
-    const m = value.trim().match(/^([0-9.]+)(\w*)$/);
+    const m = value.trim().match(/^(-?[0-9.]+)(\w*)$/);
     if (!m) {
         return null;
     }