diff --git a/esphome/components/hm3301/aqi_calculator.h b/esphome/components/hm3301/aqi_calculator.h
index 6c830f9bad..c1b47826a2 100644
--- a/esphome/components/hm3301/aqi_calculator.h
+++ b/esphome/components/hm3301/aqi_calculator.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "abstract_aqi_calculator.h"
+// https://www.airnow.gov/sites/default/files/2020-05/aqi-technical-assistance-document-sept2018.pdf
 
 namespace esphome {
 namespace hm3301 {
@@ -15,14 +16,16 @@ class AQICalculator : public AbstractAQICalculator {
   }
 
  protected:
-  static const int AMOUNT_OF_LEVELS = 6;
+  static const int AMOUNT_OF_LEVELS = 7;
 
-  int index_grid_[AMOUNT_OF_LEVELS][2] = {{0, 51}, {51, 100}, {101, 150}, {151, 200}, {201, 300}, {301, 500}};
+  int index_grid_[AMOUNT_OF_LEVELS][2] = {{0, 50},    {51, 100},  {101, 150}, {151, 200},
+                                          {201, 300}, {301, 400}, {401, 500}};
 
-  int pm2_5_calculation_grid_[AMOUNT_OF_LEVELS][2] = {{0, 12}, {13, 35}, {36, 55}, {56, 150}, {151, 250}, {251, 500}};
+  int pm2_5_calculation_grid_[AMOUNT_OF_LEVELS][2] = {{0, 12},    {13, 35},   {36, 55},  {56, 150},
+                                                      {151, 250}, {251, 350}, {351, 500}};
 
-  int pm10_0_calculation_grid_[AMOUNT_OF_LEVELS][2] = {{0, 54},    {55, 154},  {155, 254},
-                                                       {255, 354}, {355, 424}, {425, 604}};
+  int pm10_0_calculation_grid_[AMOUNT_OF_LEVELS][2] = {{0, 54},    {55, 154},  {155, 254}, {255, 354},
+                                                       {355, 424}, {425, 504}, {505, 604}};
 
   int calculate_index_(uint16_t value, int array[AMOUNT_OF_LEVELS][2]) {
     int grid_index = get_grid_index_(value, array);