diff --git a/tach/tach.ino b/tach/tach.ino
index ffffc55..e120caa 100644
--- a/tach/tach.ino
+++ b/tach/tach.ino
@@ -64,15 +64,25 @@ void loop() {
     // Store the current total snapshot for the next interval's calculation
     g_main_last_pulse_count_snapshot = current_total_snapshot;
 
+    unsigned long actual_elapsed_time = current_time - last_measurement_time;
+
     // Calculate RPM
-    // RPM = (pulses / pulses_per_revolution) / (measurement_period_ms / 1000 / 60)
-    // RPM = (pulses / pulses_per_revolution) * (60000 / measurement_period_ms)
+    // RPM = (pulses / pulses_per_revolution) / (actual_elapsed_time_ms / 1000 / 60)
+    // RPM = (pulses / pulses_per_revolution) * (60000 / actual_elapsed_time_ms)
     // Ensure floating point division for accuracy before converting to int for display
-    float rpm_float = ( (float)collected_pulses / PULSES_PER_REVOLUTION ) * (60000.0 / MEASUREMENT_PERIOD_MS);
+    float rpm_float = 0.0;
+    if (actual_elapsed_time > 0) { // Avoid division by zero
+        rpm_float = ( (float)collected_pulses / PULSES_PER_REVOLUTION ) * (60000.0 / actual_elapsed_time);
+    }
     int rpm = (int)rpm_float;
 
     show(rpm);
 
+    // Debugging output
+    Serial.print("Pulses: "); Serial.print(collected_pulses);
+    Serial.print("\tElapsed ms: "); Serial.print(actual_elapsed_time);
+    Serial.print("\tRPM: "); Serial.println(rpm);
+
     last_measurement_time = current_time;
   }
 }