diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp
index 1c33df9710..e59263e409 100644
--- a/esphome/components/web_server_idf/web_server_idf.cpp
+++ b/esphome/components/web_server_idf/web_server_idf.cpp
@@ -412,27 +412,29 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   return param;
 }
 
-optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
-  auto val = query_key_value(this->post_query_.c_str(), this->post_query_.size(), name);
-  if (val.has_value()) {
-    return val;
+/// Search post_query then URL query with a callback.
+/// Returns first truthy result, or value-initialized default.
+template<typename Func>
+static auto search_query_sources(const AsyncWebServerRequest &req, const std::string &post_query, const char *name,
+                                 Func func) -> decltype(func(nullptr, size_t{0}, name)) {
+  auto result = func(post_query.c_str(), post_query.size(), name);
+  if (result) {
+    return result;
   }
-  auto url_query = request_get_url_query(*this);
+  auto url_query = request_get_url_query(req);
   if (url_query.has_value()) {
-    return query_key_value(url_query.value().c_str(), url_query.value().size(), name);
+    return func(url_query.value().c_str(), url_query.value().size(), name);
   }
   return {};
 }
 
+optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
+  return search_query_sources(*this, this->post_query_, name,
+                              [](const char *q, size_t len, const char *k) { return query_key_value(q, len, k); });
+}
+
 bool AsyncWebServerRequest::hasArg(const char *name) {
-  if (query_has_key(this->post_query_.c_str(), this->post_query_.size(), name)) {
-    return true;
-  }
-  auto url_query = request_get_url_query(*this);
-  if (url_query.has_value()) {
-    return query_has_key(url_query.value().c_str(), url_query.value().size(), name);
-  }
-  return false;
+  return search_query_sources(*this, this->post_query_, name, query_has_key);
 }
 
 std::string AsyncWebServerRequest::arg(const char *name) {