diff --git a/examples/AlgorithmTester/AlgorithmTester.ino b/examples/AlgorithmTester/AlgorithmTester.ino
index 115fec3..69782b2 100644
--- a/examples/AlgorithmTester/AlgorithmTester.ino
+++ b/examples/AlgorithmTester/AlgorithmTester.ino
@@ -36,6 +36,8 @@ MQUnifiedsensor MQ7(placa, Voltage_Resolution, ADC_Bit_Resolution, pin7, type);
 MQUnifiedsensor MQ8(placa, Voltage_Resolution, ADC_Bit_Resolution, pin8, type);
 MQUnifiedsensor MQ9(placa, Voltage_Resolution, ADC_Bit_Resolution, pin9, type);
 
+int ratio[10] = {};
+int expectedValue[10] = {};
 
 void setup()
 {
@@ -87,6 +89,24 @@ void setup()
 
 void loop()
 {
+    // Testing MQ2 LPG
+    ratio = {};
+    expectedValue = {};    
+
+    // Testing MQ3 Benzene
+    
+    // Testing MQ4 CH4
+    
+    // Testing MQ5 H2
+    
+    // Testing MQ6 CH4
+    
+    // Testing MQ7 CO
+    
+    // Testing MQ8 H2
+    
+    // Testing MQ9 LPG
+
 
 }
 
diff --git a/src/MQUnifiedsensor.cpp b/src/MQUnifiedsensor.cpp
index 4be7c20..fef9484 100644
--- a/src/MQUnifiedsensor.cpp
+++ b/src/MQUnifiedsensor.cpp
@@ -86,6 +86,12 @@ void MQUnifiedsensor::update()
 {
   _sensor_volt = this->getVoltage();
 }
+float MQUnifiedsensor::calculatePPM(double ratio)
+{
+  if(_regressionMethod == "Exponential") _PPM= _a*pow(ratio, _b);
+  if(_regressionMethod == "Linear") _PPM= _a*ratio + _b;
+  return _PPM;  
+}
 float MQUnifiedsensor::readSensor()
 {
   //More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
diff --git a/src/MQUnifiedsensor.h b/src/MQUnifiedsensor.h
index 95c1bed..5030c72 100644
--- a/src/MQUnifiedsensor.h
+++ b/src/MQUnifiedsensor.h
@@ -29,6 +29,7 @@ class MQUnifiedsensor
     //user functions
     float calibrate(float ratioInCleanAir);
     float readSensor();
+    float calculatePPM(double ratio = 0);
     
     //get function for info
     double getR0();