diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index 6cb3b0492a..4212810234 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -1984,7 +1984,7 @@ bool QTime::setHMS(int h, int m, int s, int ms)
         mds = NullTime;                // make this invalid
         return false;
     }
-    mds = (h * SECS_PER_HOUR + m * SECS_PER_MIN + s) * MSECS_PER_SEC + ms;
+    mds = ((h * MINS_PER_HOUR + m) * SECS_PER_MIN + s) * MSECS_PER_SEC + ms;
     Q_ASSERT(mds >= 0 && mds < MSECS_PER_DAY);
     return true;
 }
@@ -2194,13 +2194,13 @@ static QTime fromIsoTimeString(QStringView string, Qt::DateFormat format, bool *
     if (string.size() > 2) {
         if (string[2] == u':' && string.size() > 4)
             minute = readInt(string.sliced(3, 2));
-        if (!minute.ok || minute.value >= 60)
+        if (!minute.ok || minute.value >= MINS_PER_HOUR)
             return QTime();
     } else if (format == Qt::TextDate) { // Requires minutes
         return QTime();
     } else if (frac.ok) {
         Q_ASSERT(!(fraction < 0.0) && fraction < 1.0);
-        fraction *= 60;
+        fraction *= MINS_PER_HOUR;
         minute.value = qulonglong(fraction);
         fraction -= minute.value;
     }
@@ -2209,13 +2209,13 @@ static QTime fromIsoTimeString(QStringView string, Qt::DateFormat format, bool *
     if (string.size() > 5) {
         if (string[5] == u':' && string.size() == 8)
             second = readInt(string.sliced(6, 2));
-        if (!second.ok || second.value >= 60)
+        if (!second.ok || second.value >= SECS_PER_MIN)
             return QTime();
     } else if (frac.ok) {
         if (format == Qt::TextDate) // Doesn't allow fraction of minutes
             return QTime();
         Q_ASSERT(!(fraction < 0.0) && fraction < 1.0);
-        fraction *= 60;
+        fraction *= SECS_PER_MIN;
         second.value = qulonglong(fraction);
         fraction -= second.value;
     }
@@ -2229,9 +2229,9 @@ static QTime fromIsoTimeString(QStringView string, Qt::DateFormat format, bool *
         // into other fields, do so:
         if (isMidnight24 || hour.value < 23 || minute.value < 59 || second.value < 59) {
             msec = 0;
-            if (++second.value == 60) {
+            if (++second.value == SECS_PER_MIN) {
                 second.value = 0;
-                if (++minute.value == 60) {
+                if (++minute.value == MINS_PER_HOUR) {
                     minute.value = 0;
                     ++hour.value;
                     // May need to propagate further via isMidnight24, see below
@@ -2388,7 +2388,8 @@ QTime QTime::fromString(const QString &string, QStringView format)
 
 bool QTime::isValid(int h, int m, int s, int ms)
 {
-    return uint(h) < 24 && uint(m) < 60 && uint(s) < SECS_PER_MIN && uint(ms) < MSECS_PER_SEC;
+    return (uint(h) < 24 && uint(m) < MINS_PER_HOUR && uint(s) < SECS_PER_MIN
+            && uint(ms) < MSECS_PER_SEC);
 }
 
 /*****************************************************************************
diff --git a/src/corelib/time/qdatetime_p.h b/src/corelib/time/qdatetime_p.h
index 0636a3a223..5ac65bc1a5 100644
--- a/src/corelib/time/qdatetime_p.h
+++ b/src/corelib/time/qdatetime_p.h
@@ -113,9 +113,10 @@ Q_DECLARE_OPERATORS_FOR_FLAGS(QDateTimePrivate::StatusFlags)
 
 namespace QtPrivate {
 namespace DateTimeConstants {
+constexpr qint64 MINS_PER_HOUR = 60;
 
 constexpr qint64 SECS_PER_MIN = 60;
-constexpr qint64 SECS_PER_HOUR = SECS_PER_MIN * 60;
+constexpr qint64 SECS_PER_HOUR = SECS_PER_MIN * MINS_PER_HOUR;
 constexpr qint64 SECS_PER_DAY = SECS_PER_HOUR * 24;
 
 constexpr qint64 MSECS_PER_SEC = 1000;
diff --git a/src/corelib/time/qlocaltime.cpp b/src/corelib/time/qlocaltime.cpp
index 5800fb0e93..70a63d132e 100644
--- a/src/corelib/time/qlocaltime.cpp
+++ b/src/corelib/time/qlocaltime.cpp
@@ -32,6 +32,11 @@ namespace {
 constexpr int tmYearFromQYear(int year) { return year - (year < 0 ? 1899 : 1900); }
 constexpr int qYearFromTmYear(int year) { return year + (year < -1899 ? 1899 : 1900); }
 
+constexpr inline qint64 tmSecsWithinDay(const struct tm &when)
+{
+    return (when.tm_hour * MINS_PER_HOUR + when.tm_min) * SECS_PER_MIN + when.tm_sec;
+}
+
 /* If mktime() returns -1, is it really an error ?
 
    It might return -1 because we're looking at the last second of 1969 and
@@ -240,7 +245,7 @@ int getCurrentStandardUtcOffset()
 #ifdef Q_OS_WIN
     TIME_ZONE_INFORMATION tzInfo;
     GetTimeZoneInformation(&tzInfo);
-    return -tzInfo.Bias * 60;
+    return -tzInfo.Bias * SECS_PER_MIN;
 #else
     qTzSet();
     const time_t curr = time(nullptr);
@@ -298,8 +303,7 @@ QDateTimePrivate::ZoneState utcToLocal(qint64 utcMillis)
                                                         local.tm_mon + 1, local.tm_mday, &jd))) {
         return {utcMillis};
     }
-    const qint64 daySeconds
-        = (local.tm_hour * 60 + local.tm_min) * 60 + local.tm_sec;
+    const qint64 daySeconds = tmSecsWithinDay(local);
     Q_ASSERT(0 <= daySeconds && daySeconds < SECS_PER_DAY);
     qint64 localSeconds, localMillis;
     if (Q_UNLIKELY(
@@ -351,7 +355,7 @@ QDateTimePrivate::ZoneState mapLocalTime(qint64 local, QDateTimePrivate::Dayligh
                        &jd))) {
         return {local, offset, dst, false};
     }
-    qint64 daySecs = tmLocal.tm_sec + 60 * (tmLocal.tm_min + 60 * tmLocal.tm_hour);
+    qint64 daySecs = tmSecsWithinDay(tmLocal);
     Q_ASSERT(0 <= daySecs && daySecs < SECS_PER_DAY);
     if (daySecs > 0 && jd < JULIAN_DAY_FOR_EPOCH) {
         ++jd;