diff --git a/components/esp_system/include/esp_intr_alloc.h b/components/esp_system/include/esp_intr_alloc.h
index 33f70b9597..a3219ef30b 100644
--- a/components/esp_system/include/esp_intr_alloc.h
+++ b/components/esp_system/include/esp_intr_alloc.h
@@ -311,7 +311,7 @@ void esp_intr_disable_source(int inum);
  */
 static inline int esp_intr_flags_to_level(int flags)
 {
-    return __builtin_ffs((flags & ESP_INTR_FLAG_LEVELMASK) >> 1) + 1;
+    return __builtin_ffs((flags & ESP_INTR_FLAG_LEVELMASK) >> 1);
 }
 
 /**@}*/