diff --git a/module01/ex02/main.c b/module01/ex02/main.c
index 77d3636..2ef21a2 100644
--- a/module01/ex02/main.c
+++ b/module01/ex02/main.c
@@ -64,6 +64,7 @@
 #define TIME_MS(ms)					(((F_CPU / PRESCALE_VALUE) * ms) / 1000)
 #define PERIOD						1000
 #define DUTY_CYCLE					10
+#define PERCENT(percent, period)	(((float)percent / 100) * period)
 
 // END MACROS
 
@@ -83,7 +84,7 @@ int main() {
     ICR1 = TIME_MS(PERIOD);
     
     // 16.9.3 : set the duty cycle to DUTY_CYCLE% of the time -> OC1A (alternate function of PORTB1, aka LED2) is cleared when TCNT1 (the counter value) equals OCR1A
-    OCR1A = TIME_MS(DUTY_CYCLE);
+    OCR1A = TIME_MS(PERCENT(DUTY_CYCLE, PERIOD));
 
     // start the timer with the prescaler
     TCCR1B |= (PRESCALE_SET);