diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index e050ec356e4..f3c7ce10266 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -179,13 +179,13 @@ public:
         = default;
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_PURE_SWAP(QString)
     void swap(QString &other) noexcept { d.swap(other.d); }
-    inline qsizetype size() const { return d.size; }
+    inline qsizetype size() const noexcept { return d.size; }
 #if QT_DEPRECATED_SINCE(6, 4)
     QT_DEPRECATED_VERSION_X_6_4("Use size() or length() instead.")
     inline qsizetype count() const { return d.size; }
 #endif
-    inline qsizetype length() const { return d.size; }
-    inline bool isEmpty() const;
+    inline qsizetype length() const noexcept { return d.size; }
+    inline bool isEmpty() const noexcept { return d.size == 0; }
     void resize(qsizetype size);
     void resize(qsizetype size, QChar fillChar);
 
@@ -1080,8 +1080,6 @@ inline const QChar QString::at(qsizetype i) const
 { Q_ASSERT(size_t(i) < size_t(size())); return QChar(d.data()[i]); }
 inline const QChar QString::operator[](qsizetype i) const
 { Q_ASSERT(size_t(i) < size_t(size())); return QChar(d.data()[i]); }
-inline bool QString::isEmpty() const
-{ return d.size == 0; }
 inline const QChar *QString::unicode() const
 { return data(); }
 inline const QChar *QString::data() const