diff --git a/gui/src/index.html b/gui/src/index.html
index d0000a4d..35c272f9 100644
--- a/gui/src/index.html
+++ b/gui/src/index.html
@@ -770,8 +770,8 @@
 						</div>
 						<div class="card-body p-2">
 							<div class="progress mb-0" style="height: 15px;">
-								<div class="progress-bar progress-bar-striped bg-primary" id="rms_level" role="progressbar" style="width: 0%" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100"></div>
-								<p class="justify-content-center d-flex position-absolute w-100">RX AUDIO LEVEL</p>
+								<div class="progress-bar progress-bar-striped bg-primary" id="rms_level" role="progressbar" style="width: 0%" aria-valuenow="0" aria-valuemin="-50" aria-valuemax="0"></div>
+								<p class="justify-content-center d-flex position-absolute w-100">-dBFS</p>
 							</div>
 							<div class="progress mb-0" style="height: 5px;">
 								<div class="progress-bar progress-bar-striped bg-warning" role="progressbar" style="width: 1%" aria-valuenow="1" aria-valuemin="0" aria-valuemax="100"></div>
diff --git a/tnc/modem.py b/tnc/modem.py
index 3db2cda9..6dd3d436 100644
--- a/tnc/modem.py
+++ b/tnc/modem.py
@@ -882,7 +882,11 @@ class RF:
                         rms_counter += 1
                         if rms_counter > 50:
                             d = np.frombuffer(self.fft_data, np.int16).astype(np.float)
-                            static.AUDIO_RMS = int(np.sqrt(np.mean(d ** 2)))
+                            # calculate RMS and then dBFS
+                            # TODO: Need to change static.AUDIO_RMS to AUDIO_DBFS somewhen
+                            rms = int(np.sqrt(np.mean(d ** 2)))
+                            static.AUDIO_RMS = 20 * np.log10(rms * np.sqrt(2) / 32768)
+
                             rms_counter = 0
 
                     # Convert data to int to decrease size