diff --git a/README.md b/README.md
index de16644..6738963 100644
--- a/README.md
+++ b/README.md
@@ -13,8 +13,8 @@ v3.11.2
 2. Execute `make`
 
 ### Settings
-* Use without printer config to use linear moves. You should look at +10% Estimation
-* Alternatively copy `config_example.json` to `config.json` and edit based on your printer settings. You should look at -15% Estimation
+* Use without printer config to use linear moves. You should look at +10% Estimation. It's not reliable on prints with lots of infill.
+* Alternatively copy `config_example.json` to `config.json` and edit based on your printer settings. You should look at -12.5% Estimation
 
 ### Usage
 `./gcode_time [file] ...`
@@ -26,4 +26,4 @@ v3.11.2
 
 `+10%       - 05:52:11`
 
-`-15%       - 04:32:09`
+`-12.5%     - 04:40:09`
diff --git a/TimeCalc.cpp b/TimeCalc.cpp
index 9ee23f0..b278f55 100644
--- a/TimeCalc.cpp
+++ b/TimeCalc.cpp
@@ -226,7 +226,8 @@ void TimeCalc::add_move(Point new_pos, double speed)
 	double vel;
 	double accel;
 	double prev_move_idx;
-	bool is_print;
+	double special_accel;
+	double de_sum;
 	static int counter = 0;
 
 	pos_new[0] = new_pos.x;
@@ -274,34 +275,32 @@ void TimeCalc::add_move(Point new_pos, double speed)
 	cout << "Vel - " << vel << endl;
 #endif
 
-	// Calculate acceleration
-	temp.clear();
-
-	// Is it a print move
-	is_print = false;
+	de_sum = 0.0;
 	for (int i = 0; i < EXTRUDER_COUNT; ++i)
 	{
-		if (0.0 != move_new.delta[3 + i])
-		{
-			is_print = true;
-			break;
-		}
+		de_sum += move_new.delta[3 + i];
 	}
 
-	// Add max acceleration for specific move to be considered
-	if (is_print)
+	// Set max acceleration for specific move to be considered
+	special_accel = 0.0;
+	if (0.0 == de_sum)
 	{
-		if (0.0 != m_print_accel_max)
-		{
-			temp.push_back(m_print_accel_max);
-		}
+		special_accel = m_travel_accel_max;
+	}
+	else if (move_new.dist == de_sum)
+	{
+		special_accel = m_retract_accel_max;
 	}
 	else
 	{
-		if (0.0 != m_travel_accel_max)
-		{
-			temp.push_back(m_travel_accel_max);
-		}
+		special_accel = m_print_accel_max;
+	}
+
+	// Calculate acceleration
+	temp.clear();
+	if (0.0 != special_accel)
+	{
+		temp.push_back(special_accel);
 	}
 
 	for (int i = 0 ; i < AXIS_COUNT; ++i)
@@ -512,3 +511,8 @@ void TimeCalc::set_travel_accel(double value)
 {
 	m_travel_accel_max = value;
 }
+
+void TimeCalc::set_retract_accel(double value)
+{
+	m_retract_accel_max = value;
+}
diff --git a/TimeCalc.h b/TimeCalc.h
index 96f8398..e41d95f 100644
--- a/TimeCalc.h
+++ b/TimeCalc.h
@@ -35,6 +35,7 @@ private:
 
 	double m_print_accel_max;
 	double m_travel_accel_max;
+	double m_retract_accel_max;
 
 	std::vector<PrinterMove> m_moves;
 
@@ -57,6 +58,7 @@ public:
 
 	void set_print_accel(double value);
 	void set_travel_accel(double value);
+	void set_retract_accel(double value);
 };
 
 #endif // TIMECALC_H_
diff --git a/config_example.json b/config_example.json
index 8f1c543..9dcd840 100644
--- a/config_example.json
+++ b/config_example.json
@@ -3,6 +3,7 @@
 	{
 		"print": 500,
 		"travel": 1000,
+		"retract": 1000,
 		"x": 500,
 		"y": 500,
 		"z": 100,
diff --git a/main.cpp b/main.cpp
index c60d775..76c600a 100644
--- a/main.cpp
+++ b/main.cpp
@@ -225,6 +225,14 @@ void init_calc(TimeCalc& calc)
 		{
 			calc.set_travel_accel(conf["acceleration"]["travel"]);
 		}
+
+		// Set Retract Acceleration
+		if (conf.contains("acceleration") &&
+			conf["acceleration"].contains("retract") &&
+			conf["acceleration"]["retract"].is_number())
+		{
+			calc.set_retract_accel(conf["acceleration"]["retract"]);
+		}
 	}
 }
 
@@ -295,8 +303,8 @@ int main(int argc, char **argv)
 		print_time(total_time * 1.1);
 		cout << endl;
 
-		cout << "-15%       - ";
-		print_time(total_time * 0.85);
+		cout << "-12.5%     - ";
+		print_time(total_time * 0.875);
 		cout << endl;
 	}
 	return 0;