diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index 3a2ae79094..413b0e82f6 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -500,15 +500,12 @@ static void set_json_id(JsonObject &root, EntityBase *obj, const char *prefix, J
   // Format: {prefix}/{device?}/{name}
   // Buffer sizes use constants from entity_base.h validated in core/config.py
 #ifdef USE_DEVICES
-  // domain + "/" + device + "/" + name + null
   static constexpr size_t ID_BUF_SIZE =
       ESPHOME_DOMAIN_MAX_LEN + 1 + ESPHOME_DEVICE_NAME_MAX_LEN + 1 + ESPHOME_FRIENDLY_NAME_MAX_LEN + 1;
-  char id_buf[ID_BUF_SIZE];
 #else
-  // domain + "/" + name + null
   static constexpr size_t ID_BUF_SIZE = ESPHOME_DOMAIN_MAX_LEN + 1 + ESPHOME_FRIENDLY_NAME_MAX_LEN + 1;
-  char id_buf[ID_BUF_SIZE];
 #endif
+  char id_buf[ID_BUF_SIZE];
   char *p = id_buf;
   memcpy(p, prefix, prefix_len);
   p += prefix_len;
diff --git a/esphome/core/entity_base.h b/esphome/core/entity_base.h
index 7208618832..4ed6a8024a 100644
--- a/esphome/core/entity_base.h
+++ b/esphome/core/entity_base.h
@@ -22,7 +22,7 @@ static constexpr size_t ESPHOME_FRIENDLY_NAME_MAX_LEN = 120;
 // Maximum domain length (longest: "alarm_control_panel" = 19)
 static constexpr size_t ESPHOME_DOMAIN_MAX_LEN = 20;
 
-// Maximum size for object_id buffer (friendly_name + margin for sanitization)
+// Maximum size for object_id buffer (friendly_name + null + margin)
 static constexpr size_t OBJECT_ID_MAX_LEN = 128;
 
 enum EntityCategory : uint8_t {