diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/common/EffortDurationBox.java b/libreplan-webapp/src/main/java/org/libreplan/web/common/EffortDurationBox.java
index 99a42b731..3ea7fc69a 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/common/EffortDurationBox.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/common/EffortDurationBox.java
@@ -38,12 +38,7 @@ public class EffortDurationBox extends Textbox {
 
     @Override
     protected Object unmarshall(Object value) {
-        EffortDuration result = EffortDuration
-                .parseFromFormattedString((String) value);
-        if (result == null) {
-            return EffortDuration.zero();
-        }
-        return result;
+        return coerceFromString((String) value);
     }
 
     @Override