diff --git a/esphome/core/time.cpp b/esphome/core/time.cpp
index 9a1a0dc492..d30dac4394 100644
--- a/esphome/core/time.cpp
+++ b/esphome/core/time.cpp
@@ -46,7 +46,7 @@ struct tm ESPTime::to_c_tm() {
   return c_tm;
 }
 
-std::string ESPTime::strftime(const char *format, size_t format_len) {
+std::string ESPTime::strftime(const char *format) {
   struct tm c_tm = this->to_c_tm();
   char buf[128];
   size_t len = ::strftime(buf, sizeof(buf), format, &c_tm);
@@ -56,7 +56,7 @@ std::string ESPTime::strftime(const char *format, size_t format_len) {
   return "ERROR";
 }
 
-std::string ESPTime::strftime(const std::string &format) { return this->strftime(format.c_str(), format.size()); }
+std::string ESPTime::strftime(const std::string &format) { return this->strftime(format.c_str()); }
 
 bool ESPTime::strptime(const std::string &time_to_parse, ESPTime &esp_time) {
   uint16_t year;
diff --git a/esphome/core/time.h b/esphome/core/time.h
index 080a0793e0..ffcfced418 100644
--- a/esphome/core/time.h
+++ b/esphome/core/time.h
@@ -55,7 +55,7 @@ struct ESPTime {
   std::string strftime(const std::string &format);
 
   /// @copydoc strftime(const std::string &format)
-  std::string strftime(const char *format, size_t format_len = 0);
+  std::string strftime(const char *format);
 
   /// Check if this ESPTime is valid (all fields in range and year is greater than 2018)
   bool is_valid() const { return this->year >= 2019 && this->fields_in_range(); }