diff --git a/src/Mod/TechDraw/App/DimensionFormatter.cpp b/src/Mod/TechDraw/App/DimensionFormatter.cpp
index 6428bbd201..7508a9d9c4 100644
--- a/src/Mod/TechDraw/App/DimensionFormatter.cpp
+++ b/src/Mod/TechDraw/App/DimensionFormatter.cpp
@@ -51,14 +51,15 @@ bool DimensionFormatter::isMultiValueSchema() const
     return false;
 }
 
+// Todo: make this enum
 //partial = 0 return the unaltered user string from the Units subsystem
 //partial = 1 return value formatted according to the format spec and preferences for
 //            useAltDecimals and showUnits
 //partial = 2 return only the unit of measure
-std::string DimensionFormatter::formatValue(qreal value,
-                                            QString qFormatSpec,
-                                            int partial,
-                                            bool isDim)
+std::string DimensionFormatter::formatValue(const qreal value,
+                                            const QString& qFormatSpec,
+                                            const int partial,
+                                            const bool isDim) const
 {
 //    Base::Console().Message("DF::formatValue() - %s isRestoring: %d\n",
 //                            m_dimension->getNameInDocument(), m_dimension->isRestoring());
@@ -190,7 +191,7 @@ std::string DimensionFormatter::formatValue(qreal value,
     return formattedValueString;
 }
 
-std::string DimensionFormatter::getFormattedToleranceValue(int partial)
+std::string DimensionFormatter::getFormattedToleranceValue(const int partial) const
 {
     QString FormatSpec = QString::fromUtf8(m_dimension->FormatSpecOverTolerance.getStrValue().data());
     QString ToleranceString;
@@ -207,7 +208,7 @@ std::string DimensionFormatter::getFormattedToleranceValue(int partial)
 }
 
 //get over and under tolerances
-std::pair<std::string, std::string> DimensionFormatter::getFormattedToleranceValues(int partial)
+std::pair<std::string, std::string> DimensionFormatter::getFormattedToleranceValues(const int partial) const
 {
     QString underFormatSpec = QString::fromUtf8(m_dimension->FormatSpecUnderTolerance.getStrValue().data());
     QString overFormatSpec = QString::fromUtf8(m_dimension->FormatSpecOverTolerance.getStrValue().data());
@@ -251,7 +252,7 @@ std::pair<std::string, std::string> DimensionFormatter::getFormattedToleranceVal
 }
 
 //partial = 2 unit only
-std::string DimensionFormatter::getFormattedDimensionValue(int partial)
+std::string DimensionFormatter::getFormattedDimensionValue(const int partial) const
 {
     QString qFormatSpec = QString::fromUtf8(m_dimension->FormatSpec.getStrValue().data());
 
@@ -308,7 +309,7 @@ std::string DimensionFormatter::getFormattedDimensionValue(int partial)
 
 // format the value using the formatSpec. Also, handle the non-standard format-
 // specifier '%w', which has the following rules: works as %f, but no trailing zeros
-QString DimensionFormatter::formatValueToSpec(double value, QString formatSpecifier)
+QString DimensionFormatter::formatValueToSpec(const double value, const QString& formatSpecifier) const
 {
     QString formattedValue;
     if (formatSpecifier.contains(QRegularExpression(QStringLiteral("%.*[wW]")))) {
@@ -329,7 +330,7 @@ QString DimensionFormatter::formatValueToSpec(double value, QString formatSpecif
     return formattedValue;
 }
 
-bool DimensionFormatter::isNumericFormat(QString formatSpecifier)
+bool DimensionFormatter::isNumericFormat(const QString& formatSpecifier) const
 {
     QRegularExpression rxFormat(QStringLiteral("%[+-]?[0-9]*\\.*[0-9]*[aefgwAEFGW]")); //printf double format spec
     QRegularExpressionMatch rxMatch;
@@ -341,7 +342,7 @@ bool DimensionFormatter::isNumericFormat(QString formatSpecifier)
 }
 
 //TODO: similar code here and above
-QStringList DimensionFormatter::getPrefixSuffixSpec(QString fSpec)
+QStringList DimensionFormatter::getPrefixSuffixSpec(const QString& fSpec) const
 {
     QStringList result;
     //find the %x.y tag in FormatSpec
@@ -404,7 +405,7 @@ std::string DimensionFormatter::getDefaultFormatSpec(bool isToleranceFormat) con
 }
 
 //true if value is too small to display using formatSpec
-bool DimensionFormatter::isTooSmall(double value, QString formatSpec)
+bool DimensionFormatter::isTooSmall(const double value, const QString& formatSpec) const
 {
     if (TechDraw::DrawUtil::fpCompare(value, 0.0)) {
         //zero values always fit, so it isn't too small
diff --git a/src/Mod/TechDraw/App/DimensionFormatter.h b/src/Mod/TechDraw/App/DimensionFormatter.h
index 30c8c8b792..e12430fa28 100644
--- a/src/Mod/TechDraw/App/DimensionFormatter.h
+++ b/src/Mod/TechDraw/App/DimensionFormatter.h
@@ -38,18 +38,18 @@ public:
 
     void setDimension(DrawViewDimension* dim) { m_dimension = dim; }
     bool isMultiValueSchema() const;
-    std::string formatValue(qreal value,
-                            QString qFormatSpec,
-                            int partial,
-                            bool isDim);
-    std::string getFormattedToleranceValue(int partial);
-    std::pair<std::string, std::string> getFormattedToleranceValues(int partial);
-    std::string getFormattedDimensionValue(int partial);
-    QStringList getPrefixSuffixSpec(QString fSpec);
+    std::string formatValue(const qreal value,
+                            const QString& qFormatSpec,
+                            const int partial,
+                            const bool isDim) const;
+    std::string getFormattedToleranceValue(const int partial) const;
+    std::pair<std::string, std::string> getFormattedToleranceValues(const int partial) const;
+    std::string getFormattedDimensionValue(const int partial) const;
+    QStringList getPrefixSuffixSpec(const QString& fSpec) const;
     std::string getDefaultFormatSpec(bool isToleranceFormat) const;
-    bool isTooSmall(double value, QString formatSpec);
-    QString formatValueToSpec(double value, QString formatSpecifier);
-    bool isNumericFormat(QString formatSpecifier);
+    bool isTooSmall(const double value, const QString& formatSpec) const;
+    QString formatValueToSpec(const double value, const QString& formatSpecifier) const;
+    bool isNumericFormat(const QString& formatSpecifier) const;
 
 private:
     DrawViewDimension* m_dimension;