diff --git a/locales/en/messages.json b/locales/en/messages.json
index 7e34bf84..3ef51cc7 100644
--- a/locales/en/messages.json
+++ b/locales/en/messages.json
@@ -3644,6 +3644,15 @@
     "pidTuningVbatPidCompensationHelp": {
         "message": "Increases the PID values to compensate when Vbat gets lower. This will give more constant flight characteristics throughout the flight. The amount of compensation that is applied is calculated from the $t(powerBatteryMaximum.message) set in the $t(tabPower.message) page, so make sure that is set to something appropriate."
     },
+    "pidTuningVbatSagCompensation": {
+        "message": "Vbat Sag Compensation"
+    },
+    "pidTuningVbatSagCompensationHelp": {
+        "message": "Gives consistent throttle and PID performance over the usable battery voltage range by compensating for battery sag. The amount of compensation can be varied between 0 and 100%. Full compensation (100%) is recommended.<br><br>Visit <a href=\"https://github.com/betaflight/betaflight/wiki/4.2-Tuning-Notes#dynamic-battery-sag-compensation\"target=\"_blank\" rel=\"noopener noreferrer\">this wiki entry</a> for more info."
+    },
+    "pidTuningVbatSagValue": {
+        "message": "%"
+    },
     "pidTuningItermRotation": {
         "message": "I Term Rotation"
     },
diff --git a/src/js/fc.js b/src/js/fc.js
index b65117f2..fe4b03a6 100644
--- a/src/js/fc.js
+++ b/src/js/fc.js
@@ -462,6 +462,7 @@ var FC = {
             ff_interpolate_sp:          0,
             ff_smooth_factor:           0,
             ff_boost:                   0,
+            vbat_sag_compensation:      0,
         };
         ADVANCED_TUNING_ACTIVE = { ...ADVANCED_TUNING };
 
diff --git a/src/js/msp/MSPHelper.js b/src/js/msp/MSPHelper.js
index b3e82b77..a2a90f77 100644
--- a/src/js/msp/MSPHelper.js
+++ b/src/js/msp/MSPHelper.js
@@ -1157,6 +1157,7 @@ MspHelper.prototype.process_data = function(dataHandler) {
                                                     ADVANCED_TUNING.ff_interpolate_sp = data.readU8();
                                                     ADVANCED_TUNING.ff_smooth_factor = data.readU8();
                                                     ADVANCED_TUNING.ff_boost = data.readU8();
+                                                    ADVANCED_TUNING.vbat_sag_compensation = data.readU8();
                                                 }
                                             }
                                         }
@@ -2098,7 +2099,8 @@ MspHelper.prototype.crunch = function(code) {
                                             if(semver.gte(CONFIG.apiVersion, API_VERSION_1_44)) {
                                                 buffer.push8(ADVANCED_TUNING.ff_interpolate_sp)
                                                       .push8(ADVANCED_TUNING.ff_smooth_factor)
-                                                      .push8(ADVANCED_TUNING.ff_boost);
+                                                      .push8(ADVANCED_TUNING.ff_boost)
+                                                      .push8(ADVANCED_TUNING.vbat_sag_compensation);
                                             }
                                         }
                                     }
diff --git a/src/js/tabs/pid_tuning.js b/src/js/tabs/pid_tuning.js
index 106e2720..e15c3ec8 100644
--- a/src/js/tabs/pid_tuning.js
+++ b/src/js/tabs/pid_tuning.js
@@ -448,11 +448,21 @@ TABS.pid_tuning.initialize = function (callback) {
             ffInterpolateCheck.change(function() {
                 const checked = $(this).is(':checked');
                 $('.ffInterpolateSp .suboption').toggle(checked);
-            });
-            ffInterpolateCheck.change();
+            }).change();
 
+            // Vbat Sag Compensation
+            const vbatSagCompensationCheck = $('input[id="vbatSagCompensation"]');
+
+            vbatSagCompensationCheck.prop('checked', ADVANCED_TUNING.vbat_sag_compensation !== 0);
+            $('input[name="vbatSagValue"]').val(ADVANCED_TUNING.vbat_sag_compensation > 0 ? ADVANCED_TUNING.vbat_sag_compensation : 100);
+
+            vbatSagCompensationCheck.change(function() {
+                const checked = $(this).is(':checked');
+                $('.vbatSagCompensation .suboption').toggle(checked);
+            }).change();
         } else {
             $('.ffInterpolateSp').hide();
+            $('.vbatSagCompensation').hide();
         }
 
         $('input[id="useIntegratedYaw"]').change(function() {
@@ -921,6 +931,7 @@ TABS.pid_tuning.initialize = function (callback) {
             ADVANCED_TUNING.ff_smooth_factor = parseInt($('input[name="ffSmoothFactor"]').val());
             ADVANCED_TUNING.ff_boost = parseInt($('input[name="ffBoost"]').val());
             FILTER_CONFIG.dyn_lpf_curve_expo = parseInt($('.pid_filter input[name="dtermLowpassDynExpo"]').val());
+            ADVANCED_TUNING.vbat_sag_compensation = $('input[id="vbatSagCompensation"]').is(':checked') ? parseInt($('input[name="vbatSagValue"]').val()) : 0;
         }
     }
 
diff --git a/src/tabs/pid_tuning.html b/src/tabs/pid_tuning.html
index c3e04544..9b1219b2 100644
--- a/src/tabs/pid_tuning.html
+++ b/src/tabs/pid_tuning.html
@@ -596,6 +596,21 @@
                                 </td>
                             </tr>
 
+                            <tr class="vbatSagCompensation">
+                                <td><input type="checkbox" id="vbatSagCompensation" class="toggle" /></td>
+                                <td colspan="2">
+                                    <span i18n="pidTuningVbatSagCompensation"></span>
+                                    <div class="helpicon cf_tip" i18n_title="pidTuningVbatSagCompensationHelp"></div>
+
+                                    <span class="vbatSagValue suboption">
+                                        <input type="number" name="vbatSagValue" step="1" min="1" max="150" />
+                                        <label for="vbatSagValue">
+                                            <span i18n="pidTuningVbatSagValue"></span>
+                                        </label>
+                                    </span>
+                                </td>
+                            </tr>
+
                             <tr class="smartfeedforward">
                                 <td><input type="checkbox" id="smartfeedforward" class="toggle" /></td>
                                 <td colspan="2">