diff --git a/esphome/components/gp8211/gp8211.cpp b/esphome/components/gp8211/gp8211.cpp
index f2e9e47024..124e7f1f5b 100644
--- a/esphome/components/gp8211/gp8211.cpp
+++ b/esphome/components/gp8211/gp8211.cpp
@@ -8,7 +8,9 @@ static const char *const TAG = "gp8211";
 
 static const uint8_t RANGE_REGISTER = 0x01;
 
-void GP8211::setup() { this->write_register(RANGE_REGISTER, &this->voltage_, 1); }
+void GP8211::setup() {
+    this->write_register(RANGE_REGISTER, reinterpret_cast<uint8_t*>(&this->voltage_), sizeof(this->voltage_));
+}
 
 void GP8211::dump_config() {
   ESP_LOGCONFIG(TAG, "GP8211:");