diff --git a/src/corelib/text/qbytearray.cpp b/src/corelib/text/qbytearray.cpp
index 23db7db3e2..d1efd2c35a 100644
--- a/src/corelib/text/qbytearray.cpp
+++ b/src/corelib/text/qbytearray.cpp
@@ -4110,13 +4110,8 @@ QByteArray QByteArray::number(qulonglong n, int base)
 QByteArray QByteArray::number(double n, char format, int precision)
 {
     QLocaleData::DoubleForm form = QLocaleData::DFDecimal;
-    uint flags = QLocaleData::ZeroPadExponent;
 
-    char lower = asciiLower(uchar(format));
-    if (format != lower)
-        flags |= QLocaleData::CapitalEorX;
-
-    switch (lower) {
+    switch (asciiLower(format)) {
         case 'f':
             form = QLocaleData::DFDecimal;
             break;
@@ -4133,7 +4128,7 @@ QByteArray QByteArray::number(double n, char format, int precision)
             break;
     }
 
-    return QLocaleData::c()->doubleToString(n, precision, form, -1, flags).toUtf8();
+    return qdtoAscii(n, form, precision, isUpperCaseAscii(format));
 }
 
 /*!
diff --git a/src/corelib/text/qlocale_tools.cpp b/src/corelib/text/qlocale_tools.cpp
index dc0460fa4e..15933c3644 100644
--- a/src/corelib/text/qlocale_tools.cpp
+++ b/src/corelib/text/qlocale_tools.cpp
@@ -628,6 +628,7 @@ static constexpr int digits(int number)
     return i;
 }
 
+// Used generically for both QString and QByteArray
 template <typename T>
 static T dtoString(double d, QLocaleData::DoubleForm form, int precision, bool uppercase)
 {
@@ -783,4 +784,9 @@ QString qdtoBasicLatin(double d, QLocaleData::DoubleForm form, int precision, bo
     return dtoString<QString>(d, form, precision, uppercase);
 }
 
+QByteArray qdtoAscii(double d, QLocaleData::DoubleForm form, int precision, bool uppercase)
+{
+    return dtoString<QByteArray>(d, form, precision, uppercase);
+}
+
 QT_END_NAMESPACE
diff --git a/src/corelib/text/qlocale_tools_p.h b/src/corelib/text/qlocale_tools_p.h
index 8648775e35..b6ffff8224 100644
--- a/src/corelib/text/qlocale_tools_p.h
+++ b/src/corelib/text/qlocale_tools_p.h
@@ -72,6 +72,7 @@ QString qulltoBasicLatin(qulonglong l, int base, bool negative);
 QString qulltoa(qulonglong l, int base, const QStringView zero);
 Q_CORE_EXPORT QString qdtoa(qreal d, int *decpt, int *sign);
 QString qdtoBasicLatin(double d, QLocaleData::DoubleForm form, int precision, bool uppercase);
+QByteArray qdtoAscii(double d, QLocaleData::DoubleForm form, int precision, bool uppercase);
 
 inline bool isZero(double d)
 {