diff --git a/src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp b/src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp
index 94e4876b6..e319267c1 100644
--- a/src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp
+++ b/src/plugins/simulator/xplane/xswiftbusserviceproxy.cpp
@@ -319,6 +319,15 @@ namespace BlackSimPlugin
             m_dbusInterface->callDBusAsync(QLatin1String("isUsingRealTime"), setterCallback(o_isRealTime));
         }
 
+        double CXSwiftBusServiceProxy::getAverageFPS() const
+        {
+            return m_dbusInterface->callDBusRet<double>(QLatin1String("getAverageFPS"));
+        }
+        void CXSwiftBusServiceProxy::getAverageFPSAsync(double *o_frameRate)
+        {
+            m_dbusInterface->callDBusAsync(QLatin1String("getAverageFPS"), setterCallback(o_frameRate));
+        }
+
         double CXSwiftBusServiceProxy::getLatitudeDeg() const
         {
             return m_dbusInterface->callDBusRet<double>(QLatin1String("getLatitudeDeg"));
diff --git a/src/plugins/simulator/xplane/xswiftbusserviceproxy.h b/src/plugins/simulator/xplane/xswiftbusserviceproxy.h
index 6963ee664..718cf13eb 100644
--- a/src/plugins/simulator/xplane/xswiftbusserviceproxy.h
+++ b/src/plugins/simulator/xplane/xswiftbusserviceproxy.h
@@ -208,6 +208,12 @@ namespace BlackSimPlugin
             void isUsingRealTimeAsync(bool *o_isRealTime);
             //! @}
 
+            //! \copydoc XSwiftBus::CService::getAverageFPS
+            //! @{
+            double getAverageFPS() const;
+            void getAverageFPSAsync(double *o_frameRate);
+            //! @}
+
             //! \copydoc XSwiftBus::CService::getLatitudeDeg
             //! @{
             double getLatitudeDeg() const;
diff --git a/src/xswiftbus/datarefs.h b/src/xswiftbus/datarefs.h
index 9bfd80a3e..16c226b16 100644
--- a/src/xswiftbus/datarefs.h
+++ b/src/xswiftbus/datarefs.h
@@ -36,6 +36,8 @@ namespace XSwiftBus
             }
         }
 
+        bool isValid() const { return m_ref; }
+
         template <typename T>
         void implSet(T);
 
@@ -60,6 +62,8 @@ namespace XSwiftBus
             }
         }
 
+        bool isValid() const { return m_ref; }
+
         template <typename T>
         void implSetAll(std::vector<T> const &);
 
@@ -108,6 +112,8 @@ namespace XSwiftBus
 
         //! Get the value of the dataref
         DataRefType get() const { return DataRefImpl::implGet<DataRefType>(); }
+
+        using DataRefImpl::isValid;
     };
 
     /*!
@@ -141,6 +147,8 @@ namespace XSwiftBus
 
         //! Get the value of a single element
         DataRefType getAt(int index) const { return ArrayDataRefImpl::implGetAt<DataRefType>(index); }
+
+        using ArrayDataRefImpl::isValid;
     };
 
     /*!
@@ -165,6 +173,9 @@ namespace XSwiftBus
             }
         }
 
+        //! True if the dataref exists
+        bool isValid() const { return m_ref; }
+
         //! Set the value of the whole string (if it is writable)
         void set(std::string const &s) { setSubstr(0, s); }
 
diff --git a/src/xswiftbus/service.cpp b/src/xswiftbus/service.cpp
index d115791f3..d2c6e3f6b 100644
--- a/src/xswiftbus/service.cpp
+++ b/src/xswiftbus/service.cpp
@@ -23,12 +23,54 @@ using namespace BlackMisc::Simulation::XPlane::QtFreeUtils;
 
 namespace XSwiftBus
 {
-    CService::CService(CSettingsProvider *settingsProvider) : CDBusObject(settingsProvider)
+    //! \private
+    struct CService::FramePeriodSampler : public CDrawable
+    {
+        DataRef<xplane::data::sim::operation::misc::frame_rate_period> m_thisFramePeriod;
+        DataRef<xplane::data::sim::time::framerate_period> m_thisFramePeriodXP11;
+        std::vector<float> m_samples;
+        float m_total = 0;
+        size_t m_lastSampleIndex = 0;
+        static constexpr size_t c_maxSampleCount = 500;
+
+        FramePeriodSampler() : CDrawable(xplm_Phase_LastCockpit, false) {}
+
+        float getAverageFPS()
+        {
+            if (m_total == 0) { return 0; }
+            const float fps = m_samples.size() / m_total;
+            m_total = 0;
+            m_samples.clear();
+            m_lastSampleIndex = 0;
+            return fps;
+        }
+
+    protected:
+        virtual void draw() override // called once per frame
+        {
+            float current = m_thisFramePeriodXP11.isValid() ? m_thisFramePeriodXP11.get() : m_thisFramePeriod.get();
+            ++m_lastSampleIndex %= c_maxSampleCount;
+            if (m_samples.size() == c_maxSampleCount)
+            {
+                m_total -= m_samples[m_lastSampleIndex];
+                m_samples[m_lastSampleIndex] = current;
+            }
+            else { m_samples.push_back(current); }
+            m_total += m_samples[m_lastSampleIndex];
+        }
+    };
+
+    CService::CService(CSettingsProvider *settingsProvider) :
+        CDBusObject(settingsProvider),
+        m_framePeriodSampler(std::make_unique<FramePeriodSampler>())
     {
         this->updateAirportsInRange();
         this->updateMessageBoxFromSettings();
+        m_framePeriodSampler->show();
     }
 
+    CService::~CService() = default;
+
     void CService::onAircraftModelChanged()
     {
         char filename[256];
@@ -63,6 +105,12 @@ namespace XSwiftBus
         return XSWIFTBUS_COMMIT;
     }
 
+    double CService::getAverageFPS()
+    {
+        if (!m_framePeriodSampler) { return 0; }
+        return static_cast<double>(m_framePeriodSampler->getAverageFPS());
+    }
+
     void CService::addTextMessage(const std::string &text, double red, double green, double blue)
     {
         if (text.empty()) { return; }
diff --git a/src/xswiftbus/service.h b/src/xswiftbus/service.h
index e247dd6be..03e21a1a2 100644
--- a/src/xswiftbus/service.h
+++ b/src/xswiftbus/service.h
@@ -40,7 +40,7 @@ namespace XSwiftBus
         CService(CSettingsProvider *settingsProvider);
 
         //! Destructor
-        virtual ~CService() override = default;
+        virtual ~CService() override;
 
         //! DBus interface name
         static const std::string &InterfaceName()
@@ -110,6 +110,11 @@ namespace XSwiftBus
         //! True if sim time is tracking operating system time
         bool isUsingRealTime() const { return m_useSystemTime.get(); }
 
+        //! Frames-per-second, averaged over the last 500 frames,
+        //! or since this function was last called, whichever is later.
+        //! \return Zero if no samples were collected since this function was last called.
+        double getAverageFPS();
+
         //! Get aircraft latitude in degrees
         double getLatitudeDeg() const { return m_latitude.get(); }
 
@@ -309,6 +314,9 @@ namespace XSwiftBus
         //! Redraw message box after reading from the settings
         void updateMessageBoxFromSettings();
 
+        struct FramePeriodSampler;
+        std::unique_ptr<FramePeriodSampler> m_framePeriodSampler;
+
         StringDataRef<xplane::data::sim::aircraft::view::acf_livery_path> m_liveryPath;
         StringDataRef<xplane::data::sim::aircraft::view::acf_ICAO> m_icao;
         StringDataRef<xplane::data::sim::aircraft::view::acf_descrip> m_descrip;