diff --git a/addons/web/static/src/js/fields/field_utils.js b/addons/web/static/src/js/fields/field_utils.js
index aabf5e2ae95..0606af0d662 100644
--- a/addons/web/static/src/js/fields/field_utils.js
+++ b/addons/web/static/src/js/fields/field_utils.js
@@ -347,7 +347,7 @@ function parseDate(value, field, options) {
         }
         if (date.year() >= 1900) {
             date.toJSON = function () {
-                return this.format('YYYY-MM-DD');
+                return this.clone().locale('en').format('YYYY-MM-DD');
             };
             return date;
         }
@@ -394,7 +394,7 @@ function parseDateTime(value, field, options) {
         }
         if (datetime.year() >= 1900) {
             datetime.toJSON = function () {
-                return this.format('YYYY-MM-DD HH:mm:ss');
+                return this.clone().locale('en').format('YYYY-MM-DD HH:mm:ss');
             };
             return datetime;
         }
diff --git a/addons/web/static/src/js/views/calendar/calendar_model.js b/addons/web/static/src/js/views/calendar/calendar_model.js
index 64eae1f746a..939e44446a8 100644
--- a/addons/web/static/src/js/views/calendar/calendar_model.js
+++ b/addons/web/static/src/js/views/calendar/calendar_model.js
@@ -16,7 +16,7 @@ var scales = [
 ];
 
 function dateToServer (date) {
-    return date.clone().utc().format('YYYY-MM-DD HH:mm:ss');
+    return date.clone().utc().locale('en').format('YYYY-MM-DD HH:mm:ss');
 }
 
 return AbstractModel.extend({