diff --git a/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp b/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
index 972f82a98..de83533bb 100644
--- a/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
+++ b/plugins/samplesink/hackrfoutput/hackrfoutputgui.cpp
@@ -203,6 +203,7 @@ void HackRFOutputGui::updateSampleRateAndFrequency()
 void HackRFOutputGui::displaySampleRate()
 {
     ui->sampleRate->blockSignals(true);
+    displayFcTooltip();
 
     if (m_sampleRateMode)
     {
@@ -229,6 +230,15 @@ void HackRFOutputGui::displaySampleRate()
     ui->sampleRate->blockSignals(false);
 }
 
+void HackRFOutputGui::displayFcTooltip()
+{
+    int32_t fShift = DeviceSampleSink::calculateFrequencyShift(
+        m_settings.m_log2Interp,
+        (DeviceSampleSink::fcPos_t) m_settings.m_fcPos,
+        m_settings.m_devSampleRate);
+    ui->fcPos->setToolTip(tr("Relative position of device center frequency: %1 kHz").arg(QString::number(fShift / 1000.0f, 'g', 5)));
+}
+
 void HackRFOutputGui::displaySettings()
 {
     blockApplySettings(true);
@@ -298,6 +308,7 @@ void HackRFOutputGui::on_sampleRate_changed(quint64 value)
         m_settings.m_devSampleRate = value * (1 << m_settings.m_log2Interp);
     }
 
+    displayFcTooltip();
     sendSettings();
 }
 
@@ -348,6 +359,7 @@ void HackRFOutputGui::on_interp_currentIndexChanged(int index)
 void HackRFOutputGui::on_fcPos_currentIndexChanged(int index)
 {
     m_settings.m_fcPos = (HackRFOutputSettings::fcPos_t) (index < 0 ? 0 : index > 2 ? 2 : index);
+    displayFcTooltip();
 	sendSettings();
 }
 
diff --git a/plugins/samplesink/hackrfoutput/hackrfoutputgui.h b/plugins/samplesink/hackrfoutput/hackrfoutputgui.h
index 4eab1cfcc..4777a148a 100644
--- a/plugins/samplesink/hackrfoutput/hackrfoutputgui.h
+++ b/plugins/samplesink/hackrfoutput/hackrfoutputgui.h
@@ -80,6 +80,7 @@ private:
 
 	void displaySettings();
     void displaySampleRate();
+    void displayFcTooltip();
 	void displayBandwidths();
 	void sendSettings();
     void updateSampleRateAndFrequency();