diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index 071fe31f69..a217f886ec 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -814,6 +814,8 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
     #error "FILAMENT_RUNOUT_SENSOR requires FIL_RUNOUT_PIN."
   #elif NUM_RUNOUT_SENSORS > E_STEPPERS
     #error "NUM_RUNOUT_SENSORS cannot exceed the number of E steppers."
+  #elif NUM_RUNOUT_SENSORS > 8
+    #error "NUM_RUNOUT_SENSORS cannot exceed 8"
   #elif NUM_RUNOUT_SENSORS > 1 && !PIN_EXISTS(FIL_RUNOUT2)
     #error "FILAMENT_RUNOUT_SENSOR with NUM_RUNOUT_SENSORS > 1 requires FIL_RUNOUT2_PIN."
   #elif NUM_RUNOUT_SENSORS > 2 && !PIN_EXISTS(FIL_RUNOUT3)
@@ -824,6 +826,10 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
     #error "FILAMENT_RUNOUT_SENSOR with NUM_RUNOUT_SENSORS > 4 requires FIL_RUNOUT5_PIN."
   #elif NUM_RUNOUT_SENSORS > 5 && !PIN_EXISTS(FIL_RUNOUT6)
     #error "FILAMENT_RUNOUT_SENSOR with NUM_RUNOUT_SENSORS > 5 requires FIL_RUNOUT6_PIN."
+  #elif NUM_RUNOUT_SENSORS > 6 && !PIN_EXISTS(FIL_RUNOUT7)
+    #error "FILAMENT_RUNOUT_SENSOR with NUM_RUNOUT_SENSORS > 6 requires FIL_RUNOUT7_PIN."
+  #elif NUM_RUNOUT_SENSORS > 7 && !PIN_EXISTS(FIL_RUNOUT8)
+    #error "FILAMENT_RUNOUT_SENSOR with NUM_RUNOUT_SENSORS > 7 requires FIL_RUNOUT8_PIN."
   #elif NONE(SDSUPPORT, PRINTJOB_TIMER_AUTOSTART)
     #error "FILAMENT_RUNOUT_SENSOR requires SDSUPPORT or PRINTJOB_TIMER_AUTOSTART."
   #elif FILAMENT_RUNOUT_DISTANCE_MM < 0