diff --git a/kdecore/util/kunitconversion.cpp b/kdecore/util/kunitconversion.cpp
index d6b842c1..57a406f8 100644
--- a/kdecore/util/kunitconversion.cpp
+++ b/kdecore/util/kunitconversion.cpp
@@ -40,6 +40,11 @@ KTemperaturePrivate::KTemperaturePrivate(const double number, const QString &uni
     } else if (unit == QString::fromUtf8("°F") || unit == QLatin1String("F") || unit == QLatin1String("Fahrenheit")) {
         m_tempunit = KTemperature::Fahrenheit;
         m_unit = QString::fromUtf8("°F");
+    // kelvin and kelvins are for KUnitConversion compatibility
+    } else if (unit == QLatin1String("K") || unit == QLatin1String("Kelvin")
+        || unit == QLatin1String("kelvin") || unit == QLatin1String("kelvins")) {
+        m_tempunit = KTemperature::Kelvin;
+        m_unit = QLatin1String("K");
     } else {
         kDebug() << "invalid unit" << unit;
         m_unit = QLatin1String("Unknown");
@@ -73,16 +78,29 @@ QString KTemperature::toString() const
 
 double KTemperature::convertTo(const KTempUnit unit) const
 {
-    static const double celsius_fahrenheit_ratio = 33.8;
-
     if (unit == d->m_tempunit) {
         return d->m_number;
     }
 
-    if (d->m_tempunit == KTemperature::Fahrenheit && unit == KTemperature::Celsius) {
-        return (d->m_number / celsius_fahrenheit_ratio);
-    } else if (d->m_tempunit == KTemperature::Celsius && unit == KTemperature::Fahrenheit) {
-        return (d->m_number * celsius_fahrenheit_ratio);
+    // for reference:
+    // https://www.rapidtables.com/convert/temperature/celsius-to-fahrenheit.html
+    // https://www.rapidtables.com/convert/temperature/celsius-to-kelvin.html
+    // https://www.rapidtables.com/convert/temperature/fahrenheit-to-celsius.html
+    // https://www.rapidtables.com/convert/temperature/fahrenheit-to-kelvin.html
+    // https://www.rapidtables.com/convert/temperature/kelvin-to-celsius.html
+    // https://www.rapidtables.com/convert/temperature/kelvin-to-fahrenheit.html
+    if (d->m_tempunit == KTemperature::Celsius && unit == KTemperature::Fahrenheit) {
+        return (d->m_number * 1.8 + 32);
+    } else if (d->m_tempunit == KTemperature::Celsius && unit == KTemperature::Kelvin) {
+        return (d->m_number + 273.15);
+    } else if (d->m_tempunit == KTemperature::Fahrenheit && unit == KTemperature::Celsius) {
+        return ((d->m_number - 32) / 1.8);
+    } else if (d->m_tempunit == KTemperature::Fahrenheit && unit == KTemperature::Kelvin) {
+        return ((d->m_number + 459.67) * 0.5);
+    } else if (d->m_tempunit == KTemperature::Kelvin && unit == KTemperature::Celsius) {
+        return (d->m_number - 273.15);
+    } else if (d->m_tempunit == KTemperature::Kelvin && unit == KTemperature::Fahrenheit) {
+        return (d->m_number * 1.8 - 459.67);
     }
     return 0.0;
 }
diff --git a/kdecore/util/kunitconversion.h b/kdecore/util/kunitconversion.h
index dc4dc922..5452eab3 100644
--- a/kdecore/util/kunitconversion.h
+++ b/kdecore/util/kunitconversion.h
@@ -33,13 +33,14 @@ public:
     enum KTempUnit {
         Invalid,
         Celsius,
-        Fahrenheit
+        Fahrenheit,
+        Kelvin
     };
 
     /*!
         @brief Constructs convertor
         @param number value of the unit
-        @param unit string representation of the unit one of: "°C", "C", "Celsius", "°F", "F" or "Fahrenheit"
+        @param unit string representation of the unit one of: "°C", "C", "Celsius", "°F", "F", "Fahrenheit", "Kelvin" or "K"
     */
     KTemperature(const double number, const QString &unit);
     ~KTemperature();
@@ -49,11 +50,11 @@ public:
     */
     double number() const;
     /*!
-        @return Short string representing the unit passed to the constructor, e.g. "°C" or "°F"
+        @return Short string representing the unit passed to the constructor, e.g. "°C", "°F" or "K"
     */
     QString unit() const;
     /*!
-        @return Combination of the number and unit as string, e.g. "12 °C" or "123 °F"
+        @return Combination of the number and unit as string, e.g. "12 °C", "123 °F" or "123 K"
     */
     QString toString() const;
     /*!