diff --git a/src/Mod/MeshPart/Gui/Tessellation.cpp b/src/Mod/MeshPart/Gui/Tessellation.cpp
index 0291e58d5a..68259a8882 100644
--- a/src/Mod/MeshPart/Gui/Tessellation.cpp
+++ b/src/Mod/MeshPart/Gui/Tessellation.cpp
@@ -193,6 +193,34 @@ struct ShapeInfo {
 };
 }
 
+void Tessellation::on_estimateMaximumEdgeLength_clicked()
+{
+    std::list<ShapeInfo> shapeObjects;
+    App::Document* activeDoc = App::GetApplication().getActiveDocument();
+    if (!activeDoc) {
+        return;
+    }
+
+    Gui::Document* activeGui = Gui::Application::Instance->getDocument(activeDoc);
+    if (!activeGui) {
+        return;
+    }
+
+    double edgeLen = 0;
+    for (auto &sel : Gui::Selection().getSelection("*",0)) {
+        auto shape = Part::Feature::getTopoShape(sel.pObject,sel.SubName);
+        if (shape.hasSubShape(TopAbs_FACE)) {
+            Base::BoundBox3d bbox = shape.getBoundBox();
+            edgeLen = std::max<double>(edgeLen, bbox.LengthX());
+            edgeLen = std::max<double>(edgeLen, bbox.LengthY());
+            edgeLen = std::max<double>(edgeLen, bbox.LengthZ());
+            shapeObjects.emplace_back(sel.pObject, sel.SubName);
+        }
+    }
+
+    ui->spinMaximumEdgeLength->setValue(edgeLen/10);
+}
+
 bool Tessellation::accept()
 {
     std::list<ShapeInfo> shapeObjects;
@@ -210,20 +238,13 @@ bool Tessellation::accept()
 
     this->document = QString::fromLatin1(activeDoc->getName());
 
-    double edgeLen = 0;
     for (auto &sel : Gui::Selection().getSelection("*",0)) {
         auto shape = Part::Feature::getTopoShape(sel.pObject,sel.SubName);
         if (shape.hasSubShape(TopAbs_FACE)) {
-            Base::BoundBox3d bbox = shape.getBoundBox();
-            edgeLen = std::max<double>(edgeLen, bbox.LengthX());
-            edgeLen = std::max<double>(edgeLen, bbox.LengthY());
-            edgeLen = std::max<double>(edgeLen, bbox.LengthZ());
-            shapeObjects.emplace_back(sel.pObject,sel.SubName);
+            shapeObjects.emplace_back(sel.pObject, sel.SubName);
         }
     }
 
-    ui->spinMaximumEdgeLength->setValue(edgeLen/10);
-
     if (shapeObjects.empty()) {
         QMessageBox::critical(this, windowTitle(),
             tr("Select a shape for meshing, first."));
diff --git a/src/Mod/MeshPart/Gui/Tessellation.h b/src/Mod/MeshPart/Gui/Tessellation.h
index 438f7918df..6b9bdc1f88 100644
--- a/src/Mod/MeshPart/Gui/Tessellation.h
+++ b/src/Mod/MeshPart/Gui/Tessellation.h
@@ -49,6 +49,7 @@ protected:
 
 private Q_SLOTS:
     void meshingMethod(int id);
+    void on_estimateMaximumEdgeLength_clicked();
     void on_comboFineness_currentIndexChanged(int);
     void on_checkSecondOrder_toggled(bool);
     void on_checkQuadDominated_toggled(bool);
diff --git a/src/Mod/MeshPart/Gui/Tessellation.ui b/src/Mod/MeshPart/Gui/Tessellation.ui
index 1eeab865fd..2a95fcbacc 100644
--- a/src/Mod/MeshPart/Gui/Tessellation.ui
+++ b/src/Mod/MeshPart/Gui/Tessellation.ui
@@ -195,6 +195,13 @@ The smallest value is 0.</string>
               </property>
              </widget>
             </item>
+            <item>
+             <widget class="QPushButton" name="estimateMaximumEdgeLength">
+              <property name="text">
+               <string>Estimate</string>
+              </property>
+             </widget>
+            </item>
            </layout>
           </item>
           <item row="1" column="0">