diff --git a/src/Gui/InputField.cpp b/src/Gui/InputField.cpp
index 1d1ec67866..6ff5b3128f 100644
--- a/src/Gui/InputField.cpp
+++ b/src/Gui/InputField.cpp
@@ -769,6 +769,12 @@ void InputField::fixup(QString& input) const
     if (localePlus != asciiPlus) {
         input.replace(localePlus, asciiPlus);
     }
+
+    // workaround for improper handling of plus sign
+    // in Building US unit system
+    // https://github.com/FreeCAD/FreeCAD/issues/11345
+    QString asciiMinusMinus(QStringLiteral("--"));
+    input.replace(asciiPlus, asciiMinusMinus);
 }
 
 QValidator::State InputField::validate(QString& input, int& pos) const