2 files changed, 3 insertions, 2 deletions
diff --git a/src/corelib/json/qjson_p.h b/src/corelib/json/qjson_p.h
index 8d6735273c..96a11cd40e 100644
--- a/src/corelib/json/qjson_p.h
+++ b/src/corelib/json/qjson_p.h
@@ -63,6 +63,7 @@
 #include <qnumeric.h>
 
 #include <limits.h>
+#include <limits>
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/corelib/json/qjsonwriter.cpp b/src/corelib/json/qjsonwriter.cpp
index c284f76cbb..8426b351f6 100644
--- a/src/corelib/json/qjsonwriter.cpp
+++ b/src/corelib/json/qjsonwriter.cpp
@@ -171,8 +171,8 @@ static void valueToJson(const QJsonPrivate::Base *b, const QJsonPrivate::Value &
         break;
     case QJsonValue::Double: {
         const double d = v.toDouble(b);
-        if (qIsFinite(d))
-            json += QByteArray::number(d);
+        if (qIsFinite(d)) // +2 to format to ensure the expected precision
+            json += QByteArray::number(d, 'g', std::numeric_limits<double>::digits10 + 2); // ::digits10 is 15
         else
             json += "null"; // +INF || -INF || NaN (see RFC4627#section2.4)
         break;