diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index ebb44c7d91..6bbf0d6a26 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -257,11 +257,9 @@ bool ESP32BLE::ble_setup_() {
 
   if (this->name_ != nullptr) {
     if (App.is_name_add_mac_suffix_enabled()) {
-      // MAC address length: 12 hex chars + null terminator
-      constexpr size_t mac_address_len = 13;
       // MAC address suffix length (last 6 characters of 12-char MAC address string)
       constexpr size_t mac_address_suffix_len = 6;
-      char mac_addr[mac_address_len];
+      char mac_addr[MAC_ADDRESS_BUFFER_SIZE];
       get_mac_address_into_buffer(mac_addr);
       const char *mac_suffix_ptr = mac_addr + mac_address_suffix_len;
       make_name_with_suffix_to(name_buffer, sizeof(name_buffer), this->name_, strlen(this->name_), '-', mac_suffix_ptr,
diff --git a/esphome/core/application.h b/esphome/core/application.h
index d3851a32da..e579080c97 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -82,11 +82,9 @@ class Application {
   void pre_setup(char *name, size_t name_len, char *friendly_name, size_t friendly_name_len) {
     arch_init();
     this->name_add_mac_suffix_ = true;
-    // MAC address length: 12 hex chars + null terminator
-    constexpr size_t mac_address_len = 13;
     // MAC address suffix length (last 6 characters of 12-char MAC address string)
     constexpr size_t mac_address_suffix_len = 6;
-    char mac_addr[mac_address_len];
+    char mac_addr[MAC_ADDRESS_BUFFER_SIZE];
     get_mac_address_into_buffer(mac_addr);
     // Overwrite the placeholder suffix in the mutable static buffers with actual MAC
     // name is always non-empty (validated by validate_hostname in Python config)