diff --git a/esphome/core/entity_base.h b/esphome/core/entity_base.h
index 70949289fd1..ccb07a4ed0b 100644
--- a/esphome/core/entity_base.h
+++ b/esphome/core/entity_base.h
@@ -21,13 +21,13 @@ extern const char *entity_uom_lookup(uint16_t index);
 extern const char *entity_icon_lookup(uint16_t index);
 
 // Bit layout for entity_string_packed_:
-//   [31..20] icon (12 bits) | [19..10] UoM (10 bits) | [9..0] device_class (10 bits)
+//   [31..24] reserved | [23..16] icon (8 bits) | [15..8] UoM (8 bits) | [7..0] device_class (8 bits)
 static constexpr uint8_t ENTITY_STR_DC_SHIFT = 0;
-static constexpr uint8_t ENTITY_STR_UOM_SHIFT = 10;
-static constexpr uint8_t ENTITY_STR_ICON_SHIFT = 20;
-static constexpr uint16_t ENTITY_STR_DC_MASK = 0x3FF;
-static constexpr uint16_t ENTITY_STR_UOM_MASK = 0x3FF;
-static constexpr uint16_t ENTITY_STR_ICON_MASK = 0xFFF;
+static constexpr uint8_t ENTITY_STR_UOM_SHIFT = 8;
+static constexpr uint8_t ENTITY_STR_ICON_SHIFT = 16;
+static constexpr uint8_t ENTITY_STR_DC_MASK = 0xFF;
+static constexpr uint8_t ENTITY_STR_UOM_MASK = 0xFF;
+static constexpr uint8_t ENTITY_STR_ICON_MASK = 0xFF;
 
 // Maximum device name length - keep in sync with validate_hostname() in esphome/core/config.py
 static constexpr size_t ESPHOME_DEVICE_NAME_MAX_LEN = 31;
@@ -105,7 +105,7 @@ class EntityBase {
   }
 
   // Set packed entity string indices — one call per entity from codegen.
-  // Bit layout: [31..20] icon (12 bits) | [19..10] UoM (10 bits) | [9..0] device_class (10 bits)
+  // Bit layout: [23..16] icon (8 bits) | [15..8] UoM (8 bits) | [7..0] device_class (8 bits)
   void set_entity_strings(uint32_t packed) { this->entity_string_packed_ = packed; }
 
   // Get device class as StringRef (from packed index)
@@ -199,7 +199,7 @@ class EntityBase {
   void calc_object_id_();
 
   StringRef name_;
-  uint32_t entity_string_packed_{0};  // bits 0-9: device_class, 10-19: uom, 20-31: icon
+  uint32_t entity_string_packed_{0};  // bits 0-7: device_class, 8-15: uom, 16-23: icon, 24-31: reserved
   uint32_t object_id_hash_{};
 #ifdef USE_DEVICES
   Device *device_{};
diff --git a/esphome/core/entity_helpers.py b/esphome/core/entity_helpers.py
index d269aecafc1..5623b5b5023 100644
--- a/esphome/core/entity_helpers.py
+++ b/esphome/core/entity_helpers.py
@@ -34,18 +34,18 @@ _KEY_ICON_IDX = "_entity_icon_idx"
 # Bit layout for entity_string_packed_ (must match C++ constants in entity_base.h):
 #
 #   uint32_t entity_string_packed_:
-#     [31 .......... 20][19 ......... 10][9 ........... 0]
-#       icon (12 bits)    UoM (10 bits)   device_class (10 bits)
-#         max 4095         max 1023         max 1023
+#     [31 ...... 24][23 ...... 16][15 ....... 8][7 ........ 0]
+#      reserved (8)  icon (8)      UoM (8)       device_class (8)
+#                    max 255       max 255        max 255
 #
 _DC_SHIFT = 0
-_UOM_SHIFT = 10
-_ICON_SHIFT = 20
+_UOM_SHIFT = 8
+_ICON_SHIFT = 16
 
 # Maximum unique strings per category (must match bit widths above)
-_MAX_DEVICE_CLASSES = 0x3FF  # 10 bits → 1023
-_MAX_UNITS = 0x3FF  # 10 bits → 1023
-_MAX_ICONS = 0xFFF  # 12 bits → 4095
+_MAX_DEVICE_CLASSES = 0xFF  # 8 bits → 255
+_MAX_UNITS = 0xFF  # 8 bits → 255
+_MAX_ICONS = 0xFF  # 8 bits → 255
 
 
 @dataclass