diff --git a/src/Base/Builder3D.h b/src/Base/Builder3D.h
index 48a9e40f14..b01d816f4d 100644
--- a/src/Base/Builder3D.h
+++ b/src/Base/Builder3D.h
@@ -208,7 +208,7 @@ public:
     {
         spaces -= 2;
     }
-    int count()
+    int count() const
     {
         return spaces;
     }
diff --git a/src/Base/Console.h b/src/Base/Console.h
index 2bf6b7ca24..79511acb14 100644
--- a/src/Base/Console.h
+++ b/src/Base/Console.h
@@ -571,7 +571,7 @@ public:
     /**
      * Returns whether a LogStyle category is active or not
      */
-    bool isActive(Base::LogStyle category)
+    bool isActive(Base::LogStyle category) const
     {
         if (category == Base::LogStyle::Log) {
             return bLog;
diff --git a/src/Base/Tools2D.h b/src/Base/Tools2D.h
index 396e42cd40..c878cff751 100644
--- a/src/Base/Tools2D.h
+++ b/src/Base/Tools2D.h
@@ -112,7 +112,7 @@ public:
     inline BoundBox2d(BoundBox2d&&) = default;
     inline BoundBox2d(double fX1, double fY1, double fX2, double fY2);
     ~BoundBox2d() = default;
-    inline bool IsValid();
+    inline bool IsValid() const;
     inline bool IsEqual(const BoundBox2d& bbox, double tolerance) const;
 
     // operators
@@ -466,7 +466,7 @@ inline BoundBox2d::BoundBox2d(double fX1, double fY1, double fX2, double fY2)
     , MaxY(std::max<double>(fY1, fY2))
 {}
 
-inline bool BoundBox2d::IsValid()
+inline bool BoundBox2d::IsValid() const
 {
     return (MaxX >= MinX) && (MaxY >= MinY);
 }
diff --git a/src/Base/Writer.cpp b/src/Base/Writer.cpp
index ef3b87f6df..24901d94fa 100644
--- a/src/Base/Writer.cpp
+++ b/src/Base/Writer.cpp
@@ -172,7 +172,7 @@ void Writer::setForceXML(bool on)
     forceXML = on;
 }
 
-bool Writer::isForceXML()
+bool Writer::isForceXML() const
 {
     return forceXML;
 }
diff --git a/src/Base/Writer.h b/src/Base/Writer.h
index c91ef819b1..ee56a9d67e 100644
--- a/src/Base/Writer.h
+++ b/src/Base/Writer.h
@@ -64,7 +64,7 @@ public:
     /// switch the writer in XML only mode (no files allowed)
     void setForceXML(bool on);
     /// check on state
-    bool isForceXML();
+    bool isForceXML() const;
     void setFileVersion(int);
     int getFileVersion() const;