diff --git a/esphome/components/packet_transport/packet_transport.cpp b/esphome/components/packet_transport/packet_transport.cpp
index da7f5f8bff..8ae2f759d0 100644
--- a/esphome/components/packet_transport/packet_transport.cpp
+++ b/esphome/components/packet_transport/packet_transport.cpp
@@ -269,7 +269,7 @@ void PacketTransport::flush_() {
 
 void PacketTransport::add_binary_data_(uint8_t key, const char *id, bool data) {
   auto len = 1 + 1 + 1 + strlen(id);
-  if (len + this->header_.size() + this->data_.size() > this->get_max_packet_size()) {
+  if (round4(this->header_.size()) + round4(this->data_.size() + len) > this->get_max_packet_size()) {
     this->flush_();
     this->init_data_();
   }
@@ -284,7 +284,7 @@ void PacketTransport::add_data_(uint8_t key, const char *id, float data) {
 
 void PacketTransport::add_data_(uint8_t key, const char *id, uint32_t data) {
   auto len = 4 + 1 + 1 + strlen(id);
-  if (len + this->header_.size() + this->data_.size() > this->get_max_packet_size()) {
+  if (round4(this->header_.size()) + round4(this->data_.size() + len) > this->get_max_packet_size()) {
     this->flush_();
     this->init_data_();
   }