diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 72ebde98b..cfb0fc133 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -867,7 +867,7 @@ void PrintConfigDef::init_fff_params()
     def->label = L("Default");
     def->full_label = L("Default infill margin");
     def->category = OptionCategory::infill;
-    def->tooltip = L("This parameter grows the top/bottom/solid layers by the specified mm to anchor them into the part. Put 0 to deactivate it. Can be a % of the width of the perimeters.");
+    def->tooltip = L("This parameter grows the top/bottom/solid layers by the specified mm to anchor them into the sparse infill and support the perimeters above. Put 0 to deactivate it. Can be a % of the width of the perimeters.");
     def->sidetext = L("mm/%");
     def->ratio_over = "perimeter_extrusion_width";
     def->min = 0;
@@ -879,7 +879,7 @@ void PrintConfigDef::init_fff_params()
     def->label = L("Bridged");
     def->full_label = L("Bridge margin");
     def->category = OptionCategory::infill;
-    def->tooltip = L("This parameter grows the bridged solid infill layers by the specified mm to anchor them into the part. Put 0 to deactivate it. Can be a % of the width of the external perimeter.");
+    def->tooltip = L("This parameter grows the bridged solid infill layers by the specified mm to anchor them into the sparse infill and over the perimeters below. Put 0 to deactivate it. Can be a % of the width of the external perimeter.");
     def->sidetext = L("mm/%");
     def->ratio_over = "external_perimeter_extrusion_width";
     def->min = 0;