diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index 81d5d507f2..ad52476dbd 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -11,7 +11,9 @@ float CalibPressureAdvance::find_optimal_PA_speed(const DynamicPrintConfig &conf
 {
     const double general_suggested_min_speed   = 100.0;
     double       filament_max_volumetric_speed = config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->get_at(0);
-    Flow         pattern_line = Flow(line_width, layer_height, config.option<ConfigOptionFloats>("nozzle_diameter")->get_at(0));
+    const float  nozzle_diameter               = config.option<ConfigOptionFloats>("nozzle_diameter")->get_at(0);
+    if (line_width <= 0.) line_width = Flow::auto_extrusion_width(frPerimeter, nozzle_diameter);
+    Flow         pattern_line = Flow(line_width, layer_height, nozzle_diameter);
     auto         pa_speed     = std::min(std::max(general_suggested_min_speed, config.option<ConfigOptionFloat>("outer_wall_speed")->value),
                                          filament_max_volumetric_speed / pattern_line.mm3_per_mm());
 
@@ -565,9 +567,10 @@ double CalibPressureAdvancePattern::flow_val() const
     double flow_mult = m_config.option<ConfigOptionFloats>("filament_flow_ratio")->get_at(0);
     double nozzle_diameter = m_config.option<ConfigOptionFloats>("nozzle_diameter")->get_at(0);
     double line_width = m_config.get_abs_value("line_width", nozzle_diameter);
+    if (line_width <= 0.) line_width = Flow::auto_extrusion_width(frPerimeter, nozzle_diameter);
     double layer_height = m_config.get_abs_value("layer_height");
     double speed = speed_perimeter();
-    Flow pattern_line = Flow(line_width, layer_height, m_config.option<ConfigOptionFloats>("nozzle_diameter")->get_at(0));
+    Flow pattern_line = Flow(line_width, layer_height, nozzle_diameter);
 
     return speed * pattern_line.mm3_per_mm() * flow_mult;
 };
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index 32c516c778..c9a950d886 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -286,7 +286,9 @@ protected:
     {
         // TODO: FIXME: find out current filament/extruder?
         const double nozzle_diameter = m_config.opt_float("nozzle_diameter", 0);
-        return m_config.get_abs_value("line_width", nozzle_diameter);
+        const double width = m_config.get_abs_value("line_width", nozzle_diameter);
+        if (width <= 0.) return Flow::auto_extrusion_width(frExternalPerimeter, nozzle_diameter);
+        return width;
     };
     int    wall_count() const { return m_config.option<ConfigOptionInt>("wall_loops")->value; };
 
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index c05e6b4c5e..cb44a641fb 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -9592,9 +9592,7 @@ void Plater::_calib_pa_pattern(const Calib_Params& params)
     if (speeds.empty()) {
         double speed = CalibPressureAdvance::find_optimal_PA_speed(
             wxGetApp().preset_bundle->full_config(),
-            (fabs(print_config.get_abs_value("line_width", nozzle_diameter)) <= DBL_EPSILON) ?
-                (nozzle_diameter * 1.125) :
-                print_config.get_abs_value("line_width", nozzle_diameter),
+            print_config.get_abs_value("line_width", nozzle_diameter),
             print_config.get_abs_value("layer_height"), 0);
         print_config.set_key_value("outer_wall_speed", new ConfigOptionFloat(speed));