diff --git a/src/Mod/Sketcher/App/planegcs/GCS.cpp b/src/Mod/Sketcher/App/planegcs/GCS.cpp
index 85ac511c78..9b2ce7e82d 100644
--- a/src/Mod/Sketcher/App/planegcs/GCS.cpp
+++ b/src/Mod/Sketcher/App/planegcs/GCS.cpp
@@ -812,7 +812,7 @@ int System::addConstraintTangentCircumf(Point &p1, Point &p2, double *rad1, doub
     return addConstraint(constr);
 }
 
-int System::addConstraintTangentAtBSplineKnot(BSpline &b, Line &l, size_t knotindex, int tagId, bool driving)
+int System::addConstraintTangentAtBSplineKnot(BSpline &b, Line &l, unsigned int knotindex, int tagId, bool driving)
 {
     Constraint *constr = new ConstraintSlopeAtBSplineKnot(b, l, knotindex);
     constr->setTag(tagId);
diff --git a/src/Mod/Sketcher/App/planegcs/GCS.h b/src/Mod/Sketcher/App/planegcs/GCS.h
index aa55774cdd..6de364afa6 100644
--- a/src/Mod/Sketcher/App/planegcs/GCS.h
+++ b/src/Mod/Sketcher/App/planegcs/GCS.h
@@ -257,7 +257,7 @@ namespace GCS
                                         int tagId=0, bool driving = true);
         int addConstraintTangentCircumf(Point &p1, Point &p2, double *rd1, double *rd2,
                                         bool internal=false, int tagId=0, bool driving = true);
-        int addConstraintTangentAtBSplineKnot(BSpline &b, Line &l, size_t knotindex,
+        int addConstraintTangentAtBSplineKnot(BSpline &b, Line &l, unsigned int knotindex,
                                               int tagId=0, bool driving = true);
 
         // derived constraints
diff --git a/src/Mod/Sketcher/App/planegcs/Geo.cpp b/src/Mod/Sketcher/App/planegcs/Geo.cpp
index 1ed70be814..9c595dcde8 100644
--- a/src/Mod/Sketcher/App/planegcs/Geo.cpp
+++ b/src/Mod/Sketcher/App/planegcs/Geo.cpp
@@ -712,7 +712,7 @@ BSpline* BSpline::Copy()
     return crv;
 }
 
-double BSpline::getLinCombFactor(double x, size_t k, size_t i, size_t p)
+double BSpline::getLinCombFactor(double x, size_t k, size_t i, unsigned int p)
 {
     // Adapted to C++ from the python implementation in the Wikipedia page for de Boor algorithm
     // https://en.wikipedia.org/wiki/De_Boor%27s_algorithm.
@@ -734,7 +734,7 @@ double BSpline::getLinCombFactor(double x, size_t k, size_t i, size_t p)
         return 0.0;
     d[idxOfPole] = 1.0;
 
-    for (size_t r = 1; static_cast<int>(r) < p + 1; ++r) {
+    for (size_t r = 1; r < p + 1; ++r) {
         for (size_t j = p; j > r - 1; --j) {
             double alpha =
                 (x - flattenedknots[j + k - p]) /
@@ -746,7 +746,7 @@ double BSpline::getLinCombFactor(double x, size_t k, size_t i, size_t p)
     return d[p];
 }
 
-double BSpline::splineValue(double x, size_t k, size_t p, VEC_D& d, const VEC_D& flatknots)
+double BSpline::splineValue(double x, size_t k, unsigned int p, VEC_D& d, const VEC_D& flatknots)
 {
     for (size_t r = 1; r < p + 1; ++r) {
         for (size_t j = p; j > r - 1; --j) {
diff --git a/src/Mod/Sketcher/App/planegcs/Geo.h b/src/Mod/Sketcher/App/planegcs/Geo.h
index 0ab64871ef..6a4b24b5f4 100644
--- a/src/Mod/Sketcher/App/planegcs/Geo.h
+++ b/src/Mod/Sketcher/App/planegcs/Geo.h
@@ -304,7 +304,7 @@ namespace GCS
         /// k is the range in `flattenedknots` that contains x
         /// i is index of control point
         /// p is the degree
-        double getLinCombFactor(double x, size_t k, size_t i, size_t p);
+        double getLinCombFactor(double x, size_t k, size_t i, unsigned int p);
         inline double getLinCombFactor(double x, size_t k, size_t i)
         { return getLinCombFactor(x, k, i, degree); }
         void setupFlattenedKnots();
@@ -314,7 +314,7 @@ namespace GCS
         /// p is the degree
         /// d is the vector of (relevant) poles (this will be changed)
         /// flatknots is the vector of knots
-        static double splineValue(double x, size_t k, size_t p, VEC_D& d, const VEC_D& flatknots);
+        static double splineValue(double x, size_t k, unsigned int p, VEC_D& d, const VEC_D& flatknots);
     };
 
 } //namespace GCS