diff --git a/esphome/components/sensor/__init__.py b/esphome/components/sensor/__init__.py
index 2acdaed589..650f5ed826 100644
--- a/esphome/components/sensor/__init__.py
+++ b/esphome/components/sensor/__init__.py
@@ -810,7 +810,7 @@ async def calibrate_polynomial_filter_to_code(config, filter_id):
     # Column vector
     b = [[v] for v in y]
     res = [v[0] for v in _lstsq(a, b)]
-    return cg.new_Pvariable(filter_id, res)
+    return cg.new_Pvariable(filter_id, cg.TemplateArguments(len(res)), res)
 
 
 def validate_clamp(config):
diff --git a/esphome/components/sensor/filter.cpp b/esphome/components/sensor/filter.cpp
index 90e1b82793..a226ed5af1 100644
--- a/esphome/components/sensor/filter.cpp
+++ b/esphome/components/sensor/filter.cpp
@@ -383,14 +383,11 @@ optional<float> calibrate_linear_compute(const std::array<float, 3> *functions,
   return NAN;
 }
 
-CalibratePolynomialFilter::CalibratePolynomialFilter(std::initializer_list<float> coefficients)
-    : coefficients_(coefficients) {}
-
-optional<float> CalibratePolynomialFilter::new_value(float value) {
+optional<float> calibrate_polynomial_compute(const float *coefficients, size_t count, float value) {
   float res = 0.0f;
   float x = 1.0f;
-  for (const auto &coefficient : this->coefficients_) {
-    res += x * coefficient;
+  for (size_t i = 0; i < count; i++) {
+    res += x * coefficients[i];
     x *= value;
   }
   return res;
diff --git a/esphome/components/sensor/filter.h b/esphome/components/sensor/filter.h
index 7560c28986..8bb495edd2 100644
--- a/esphome/components/sensor/filter.h
+++ b/esphome/components/sensor/filter.h
@@ -566,13 +566,26 @@ template<size_t N> class CalibrateLinearFilter : public Filter {
   std::array<std::array<float, 3>, N> linear_functions_{};
 };
 
-class CalibratePolynomialFilter : public Filter {
+/// Non-template helper for polynomial calibration (implementation in filter.cpp)
+optional<float> calibrate_polynomial_compute(const float *coefficients, size_t count, float value);
+
+/// N is set by code generation to match the exact number of polynomial coefficients.
+template<size_t N> class CalibratePolynomialFilter : public Filter {
  public:
-  explicit CalibratePolynomialFilter(std::initializer_list<float> coefficients);
-  optional<float> new_value(float value) override;
+  explicit CalibratePolynomialFilter(std::initializer_list<float> coefficients) {
+    size_t i = 0;
+    for (float c : coefficients) {
+      if (i >= N)
+        break;
+      this->coefficients_[i++] = c;
+    }
+  }
+  optional<float> new_value(float value) override {
+    return calibrate_polynomial_compute(this->coefficients_.data(), N, value);
+  }
 
  protected:
-  FixedVector<float> coefficients_;
+  std::array<float, N> coefficients_{};
 };
 
 class ClampFilter : public Filter {