diff --git a/esphome/components/api/api_frame_helper_plaintext.cpp b/esphome/components/api/api_frame_helper_plaintext.cpp
index 3c57821595..e97b558fa3 100644
--- a/esphome/components/api/api_frame_helper_plaintext.cpp
+++ b/esphome/components/api/api_frame_helper_plaintext.cpp
@@ -253,9 +253,10 @@ APIError APIPlaintextFrameHelper::write_protobuf_messages(ProtoWriteBuffer buffe
 
   for (const auto &msg : messages) {
     // Calculate varint sizes for header layout using inline ternary to avoid varint_slow call overhead
-    uint8_t size_varint_len =
-        msg.payload_size < ProtoSize::VARINT_MAX_1_BYTE ? 1 : (msg.payload_size < ProtoSize::VARINT_MAX_2_BYTE ? 2 : 3);
-    uint8_t type_varint_len = msg.message_type < ProtoSize::VARINT_MAX_1_BYTE ? 1 : 2;
+    uint8_t size_varint_len = msg.payload_size < ProtoSize::VARINT_THRESHOLD_1_BYTE
+                                  ? 1
+                                  : (msg.payload_size < ProtoSize::VARINT_THRESHOLD_2_BYTE ? 2 : 3);
+    uint8_t type_varint_len = msg.message_type < ProtoSize::VARINT_THRESHOLD_1_BYTE ? 1 : 2;
     uint8_t total_header_len = 1 + size_varint_len + type_varint_len;
 
     // Calculate where to start writing the header
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index 0ffabe22a9..97a19f8007 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -474,10 +474,10 @@ class ProtoDecodableMessage : public ProtoMessage {
 class ProtoSize {
  public:
   // Varint encoding thresholds: values below each threshold fit in N bytes
-  static constexpr uint32_t VARINT_MAX_1_BYTE = 1 << 7;   // 128
-  static constexpr uint32_t VARINT_MAX_2_BYTE = 1 << 14;  // 16384
-  static constexpr uint32_t VARINT_MAX_3_BYTE = 1 << 21;  // 2097152
-  static constexpr uint32_t VARINT_MAX_4_BYTE = 1 << 28;  // 268435456
+  static constexpr uint32_t VARINT_THRESHOLD_1_BYTE = 1 << 7;   // 128
+  static constexpr uint32_t VARINT_THRESHOLD_2_BYTE = 1 << 14;  // 16384
+  static constexpr uint32_t VARINT_THRESHOLD_3_BYTE = 1 << 21;  // 2097152
+  static constexpr uint32_t VARINT_THRESHOLD_4_BYTE = 1 << 28;  // 268435456
 
   /**
    * @brief Calculates the size in bytes needed to encode a uint32_t value as a varint
@@ -486,7 +486,7 @@ class ProtoSize {
    * @return The number of bytes needed to encode the value
    */
   static constexpr inline uint32_t ESPHOME_ALWAYS_INLINE varint(uint32_t value) {
-    if (value < VARINT_MAX_1_BYTE) [[likely]]
+    if (value < VARINT_THRESHOLD_1_BYTE) [[likely]]
       return 1;  // Fast path: 7 bits, most common case
     if (__builtin_is_constant_evaluated())
       return varint_wide(value);
@@ -498,11 +498,11 @@ class ProtoSize {
   static uint32_t varint_slow(uint32_t value) __attribute__((noinline));
   // Shared cascade for values >= 128 (used by both constexpr and noinline paths)
   static constexpr inline uint32_t ESPHOME_ALWAYS_INLINE varint_wide(uint32_t value) {
-    if (value < VARINT_MAX_2_BYTE)
+    if (value < VARINT_THRESHOLD_2_BYTE)
       return 2;
-    if (value < VARINT_MAX_3_BYTE)
+    if (value < VARINT_THRESHOLD_3_BYTE)
       return 3;
-    if (value < VARINT_MAX_4_BYTE)
+    if (value < VARINT_THRESHOLD_4_BYTE)
       return 4;
     return 5;
   }