diff --git a/sdrgui/gui/glspectrumgui.cpp b/sdrgui/gui/glspectrumgui.cpp
index d120d8199..2b07d1542 100644
--- a/sdrgui/gui/glspectrumgui.cpp
+++ b/sdrgui/gui/glspectrumgui.cpp
@@ -233,6 +233,7 @@ void GLSpectrumGUI::on_fftOverlap_valueChanged(int value)
     ui->fftOverlapText->setText(tr("%1").arg(m_settings.m_fftOverlap));
     setMaximumOverlap();
     applySettings();
+    setAveragingToolitp();
 }
 
 void GLSpectrumGUI::on_averagingMode_currentIndexChanged(int index)
@@ -497,10 +498,12 @@ void GLSpectrumGUI::setAveragingToolitp()
     if (m_glSpectrum)
     {
         QString s;
+        float halfSize = m_settings.m_fftSize / 2;
+        float overlapFactor = (halfSize - m_settings.m_fftOverlap) / halfSize;
         float averagingTime = (m_settings.m_fftSize * (getAveragingValue(m_settings.m_averagingIndex, m_settings.m_averagingMode) == 0 ?
             1 :
             getAveragingValue(m_settings.m_averagingIndex, m_settings.m_averagingMode))) / (float) m_glSpectrum->getSampleRate();
-        setNumberStr(averagingTime, 2, s);
+        setNumberStr(averagingTime*overlapFactor, 2, s);
         ui->averaging->setToolTip(QString("Number of averaging samples (avg time: %1s)").arg(s));
     }
     else