diff --git a/esphome/components/ld2410/ld2410.cpp b/esphome/components/ld2410/ld2410.cpp
index 32e49c643f..914de8e145 100644
--- a/esphome/components/ld2410/ld2410.cpp
+++ b/esphome/components/ld2410/ld2410.cpp
@@ -8,6 +8,7 @@
 #endif
 
 #include "esphome/core/application.h"
+#include "esphome/core/helpers.h"
 
 namespace esphome::ld2410 {
 
@@ -178,7 +179,7 @@ static inline bool validate_header_footer(const uint8_t *header_footer, const ui
 }
 
 void LD2410Component::dump_config() {
-  char mac_s[18];
+  char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
   char version_s[20];
   const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
   ld24xx::format_version_str(this->version_, version_s);
@@ -511,7 +512,7 @@ bool LD2410Component::handle_ack_data_() {
         std::memcpy(this->mac_address_, &this->buffer_data_[10], sizeof(this->mac_address_));
       }
 
-      char mac_s[18];
+      char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
       const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
       ESP_LOGV(TAG, "MAC address: %s", mac_str);
 #ifdef USE_TEXT_SENSOR
diff --git a/esphome/components/ld2410/ld2410.h b/esphome/components/ld2410/ld2410.h
index a0cce36d16..061846f1f1 100644
--- a/esphome/components/ld2410/ld2410.h
+++ b/esphome/components/ld2410/ld2410.h
@@ -121,7 +121,7 @@ class LD2410Component final : public Component, public uart::UARTDevice {
   uint8_t out_pin_level_ = 0;
   uint8_t buffer_pos_ = 0;  // where to resume processing/populating buffer
   uint8_t buffer_data_[MAX_LINE_LENGTH];
-  uint8_t mac_address_[6] = {0, 0, 0, 0, 0, 0};
+  uint8_t mac_address_[MAC_ADDRESS_SIZE] = {0, 0, 0, 0, 0, 0};
   uint8_t version_[6] = {0, 0, 0, 0, 0, 0};
   bool bluetooth_on_{false};
 #ifdef USE_NUMBER
diff --git a/esphome/components/ld2412/ld2412.cpp b/esphome/components/ld2412/ld2412.cpp
index 093e8c72dc..7041b7539f 100644
--- a/esphome/components/ld2412/ld2412.cpp
+++ b/esphome/components/ld2412/ld2412.cpp
@@ -197,7 +197,7 @@ static inline bool validate_header_footer(const uint8_t *header_footer, const ui
 }
 
 void LD2412Component::dump_config() {
-  char mac_s[18];
+  char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
   char version_s[20];
   const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
   ld24xx::format_version_str(this->version_, version_s);
@@ -555,7 +555,7 @@ bool LD2412Component::handle_ack_data_() {
         std::memcpy(this->mac_address_, &this->buffer_data_[10], sizeof(this->mac_address_));
       }
 
-      char mac_s[18];
+      char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
       const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
       ESP_LOGV(TAG, "MAC address: %s", mac_str);
 #ifdef USE_TEXT_SENSOR
diff --git a/esphome/components/ld2412/ld2412.h b/esphome/components/ld2412/ld2412.h
index f722f938ae..a52402c2ea 100644
--- a/esphome/components/ld2412/ld2412.h
+++ b/esphome/components/ld2412/ld2412.h
@@ -124,7 +124,7 @@ class LD2412Component final : public Component, public uart::UARTDevice {
   uint8_t out_pin_level_ = 0;
   uint8_t buffer_pos_ = 0;  // where to resume processing/populating buffer
   uint8_t buffer_data_[MAX_LINE_LENGTH];
-  uint8_t mac_address_[6] = {0, 0, 0, 0, 0, 0};
+  uint8_t mac_address_[MAC_ADDRESS_SIZE] = {0, 0, 0, 0, 0, 0};
   uint8_t version_[6] = {0, 0, 0, 0, 0, 0};
   bool bluetooth_on_{false};
   bool dynamic_background_correction_active_{false};
diff --git a/esphome/components/ld2450/ld2450.cpp b/esphome/components/ld2450/ld2450.cpp
index 0dc2638aad..4b41d63a88 100644
--- a/esphome/components/ld2450/ld2450.cpp
+++ b/esphome/components/ld2450/ld2450.cpp
@@ -184,7 +184,7 @@ void LD2450Component::setup() {
 }
 
 void LD2450Component::dump_config() {
-  char mac_s[18];
+  char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
   char version_s[20];
   const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
   ld24xx::format_version_str(this->version_, version_s);
@@ -680,7 +680,7 @@ bool LD2450Component::handle_ack_data_() {
         std::memcpy(this->mac_address_, &this->buffer_data_[10], sizeof(this->mac_address_));
       }
 
-      char mac_s[18];
+      char mac_s[MAC_ADDRESS_PRETTY_BUFFER_SIZE];
       const char *mac_str = ld24xx::format_mac_str(this->mac_address_, mac_s);
       ESP_LOGV(TAG, "MAC address: %s", mac_str);
 #ifdef USE_TEXT_SENSOR
diff --git a/esphome/components/ld2450/ld2450.h b/esphome/components/ld2450/ld2450.h
index 10f9bb874a..c4f06ad224 100644
--- a/esphome/components/ld2450/ld2450.h
+++ b/esphome/components/ld2450/ld2450.h
@@ -169,7 +169,7 @@ class LD2450Component : public Component, public uart::UARTDevice {
   uint32_t moving_presence_millis_ = 0;
   uint32_t timeout_ = 5;
   uint8_t buffer_data_[MAX_LINE_LENGTH];
-  uint8_t mac_address_[6] = {0, 0, 0, 0, 0, 0};
+  uint8_t mac_address_[MAC_ADDRESS_SIZE] = {0, 0, 0, 0, 0, 0};
   uint8_t version_[6] = {0, 0, 0, 0, 0, 0};
   uint8_t buffer_pos_ = 0;  // where to resume processing/populating buffer
   uint8_t zone_type_ = 0;
diff --git a/esphome/components/ld24xx/ld24xx.h b/esphome/components/ld24xx/ld24xx.h
index cba1b68a15..deac04e86f 100644
--- a/esphome/components/ld24xx/ld24xx.h
+++ b/esphome/components/ld24xx/ld24xx.h
@@ -45,8 +45,7 @@ static const char *const VERSION_FMT = "%u.%02X.%02X%02X%02X%02X";
 
 // Helper function to format MAC address with stack allocation
 // Returns pointer to UNKNOWN_MAC constant or formatted buffer
-// Buffer must be exactly 18 bytes (17 for "XX:XX:XX:XX:XX:XX" + null terminator)
-inline const char *format_mac_str(const uint8_t *mac_address, std::span<char, 18> buffer) {
+inline const char *format_mac_str(const uint8_t *mac_address, std::span<char, MAC_ADDRESS_PRETTY_BUFFER_SIZE> buffer) {
   if (mac_address_is_valid(mac_address)) {
     format_mac_addr_upper(mac_address, buffer.data());
     return buffer.data();