diff --git a/src/general_menus.cpp b/src/general_menus.cpp
index cc894a950..91b952b24 100644
--- a/src/general_menus.cpp
+++ b/src/general_menus.cpp
@@ -892,8 +892,8 @@ void menuGeneralDiagAna(uint8_t event)
   lcd_putsLeft(5*FH, STR_BATT_CALIB);
   static uint32_t adcBatt;
   adcBatt = ((adcBatt * 7) + anaIn(8)) / 8; // running average, sourced directly (to avoid unending debate :P)
-  uint32_t batCalV = ( adcBatt + adcBatt*(g_eeGeneral.vBatCalib)/128 ) * 33 ;
-  batCalV /= 512  ;
+  uint32_t batCalV = ( adcBatt + adcBatt*(g_eeGeneral.vBatCalib)/128 ) * 15 ;
+  batCalV /= 256  ;
   putsVolts(LEN_CALIB_FIELDS*FW+4*FW, 5*FH, batCalV, (m_posVert==1 ? INVERS : 0));
 #else
   lcd_putsLeft(6*FH-2, STR_BATT_CALIB);
diff --git a/src/open9x.cpp b/src/open9x.cpp
index 0898b865b..ea2ba4180 100644
--- a/src/open9x.cpp
+++ b/src/open9x.cpp
@@ -2944,8 +2944,8 @@ void perMain()
     counter = 10;
 #if defined(PCBX9D)
     int32_t instant_vbat = anaIn(TX_VOLTAGE);
-    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 33 ;
-    instant_vbat /= 512  ;
+    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 15 ;
+    instant_vbat /= 256  ;
 #elif defined(PCBSKY9X)
     int32_t instant_vbat = anaIn(TX_VOLTAGE);
     instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 4191 ;