diff --git a/esphome/components/ac_dimmer/ac_dimmer.cpp b/esphome/components/ac_dimmer/ac_dimmer.cpp
index 1d0cd8d0ab..16101a1c2c 100644
--- a/esphome/components/ac_dimmer/ac_dimmer.cpp
+++ b/esphome/components/ac_dimmer/ac_dimmer.cpp
@@ -121,11 +121,8 @@ void IRAM_ATTR HOT AcDimmerDataStore::gpio_intr() {
       // calculate time until enable in µs: (1.0-value)*cycle_time, but with integer arithmetic
       // also take into account min_power
       auto min_us = this->cycle_time_us * this->min_power / 1000;
-      // calculate required value to provide a true RMS voltage output
-      this->enable_time_us =
-          std::max((uint32_t) 1, (uint32_t)((65535 - (acos(1 - (2 * this->value / 65535.0)) / 3.14159 * 65535)) *
-                                            (this->cycle_time_us - min_us)) /
-                                     65535);
+      this->enable_time_us = std::max((uint32_t) 1, ((65535 - this->value) * (this->cycle_time_us - min_us)) / 65535);
+
       if (this->method == DIM_METHOD_LEADING_PULSE) {
         // Minimum pulse time should be enough for the triac to trigger when it is close to the ZC zone
         // this is for brightness near 99%
@@ -206,6 +203,7 @@ void AcDimmer::setup() {
 #endif
 }
 void AcDimmer::write_state(float state) {
+  state = std::acos(1 - (2 * state)) / 3.14159;  // RMS power compensation
   auto new_value = static_cast<uint16_t>(roundf(state * 65535));
   if (new_value != 0 && this->store_.value == 0)
     this->store_.init_cycle = this->init_with_half_cycle_;