diff --git a/cores/esp32/WString.cpp b/cores/esp32/WString.cpp
index 6632aa5f85d..7210dfbfbc4 100644
--- a/cores/esp32/WString.cpp
+++ b/cores/esp32/WString.cpp
@@ -910,7 +910,7 @@ long String::toInt(void) const {
 
 float String::toFloat(void) const {
   if (buffer()) {
-    return atof(buffer());
+    return static_cast<float>(atof(buffer()));
   }
   return 0;
 }