diff --git a/src/slic3r/GUI/ExtrusionCalibration.cpp b/src/slic3r/GUI/ExtrusionCalibration.cpp
index d45b4db2c..945069b01 100644
--- a/src/slic3r/GUI/ExtrusionCalibration.cpp
+++ b/src/slic3r/GUI/ExtrusionCalibration.cpp
@@ -510,7 +510,7 @@ bool ExtrusionCalibration::check_k_validation(wxString k_text)
         ;
     }
 
-    if (k < 0 || k > 0.3)
+    if (k < MIN_PA_K_VALUE || k > MAX_PA_K_VALUE)
         return false;
     return true;
 }
@@ -534,7 +534,7 @@ bool ExtrusionCalibration::check_k_n_validation(wxString k_text, wxString n_text
     catch (...) {
         ;
     }
-    if (k < 0 || k > 0.5)
+    if (k < MIN_PA_K_VALUE || k > MAX_PA_K_VALUE)
         return false;
     if (n < 0.6 || n > 2.0)
         return false;