diff --git a/lib/treppe/treppe.cpp b/lib/treppe/treppe.cpp
index 2bfa2d5..06fff63 100644
--- a/lib/treppe/treppe.cpp
+++ b/lib/treppe/treppe.cpp
@@ -268,7 +268,7 @@ void Treppe::setup()
 }
 
 void Treppe::set_idle_prozent(int prozent) {
-  uint16_t new_pwm = 0xFFF * prozent / 100;
+  uint16_t new_pwm = active_pwm * prozent / 100;
   set_idle_pwm(new_pwm);
 }