JavaFX Label create a loan calculator

import javafx.application.Application;
import javafx.geometry.HPos;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class Main extends Application {
   private TextField tfInvestmentAmount = new TextField();
   private TextField tfNumberOfYears = new TextField();
   private TextField tfAnnualInterestRate = new TextField();
   private TextField tfFutureValue = new TextField();
   private Button btCalculate = new Button("Calculate");

   @Override//from   w  ww  .j  a  va  2 s .co m
   public void start(Stage primaryStage) {
      // Create UI
      GridPane pane = new GridPane();
      pane.setVgap(5);
      pane.setHgap(5);
      pane.add(new Label("Investment Amount:"), 0, 0);
      pane.add(tfInvestmentAmount, 1, 0);
      pane.add(new Label("Number Of Years:"), 0, 1);
      pane.add(tfNumberOfYears, 1, 1);
      pane.add(new Label("Annual Interest Rate:"), 0, 2);
      pane.add(tfAnnualInterestRate, 1, 2);
      pane.add(new Label("Future value:"), 0, 3);
      pane.add(tfFutureValue, 1, 3);
      pane.add(btCalculate, 1, 4);

      // Set UI properties
      pane.setAlignment(Pos.CENTER);
      tfInvestmentAmount.setAlignment(Pos.BOTTOM_RIGHT);
      tfNumberOfYears.setAlignment(Pos.BOTTOM_RIGHT);
      tfAnnualInterestRate.setAlignment(Pos.BOTTOM_RIGHT);
      tfFutureValue.setAlignment(Pos.BOTTOM_RIGHT);
      tfFutureValue.setEditable(false);
      GridPane.setHalignment(btCalculate, HPos.RIGHT);
      pane.setPadding(new Insets(10, 10, 10, 10));

      // Process events
      btCalculate.setOnAction(e -> futureValue());

      // Create a scene and place it in the stage
      Scene scene = new Scene(pane);
      primaryStage.setTitle("java2s.com");
      primaryStage.setScene(scene);
      primaryStage.show();
   }

   private void futureValue() {
      double investmentAmount = Double.parseDouble(tfInvestmentAmount.getText());
      int years = Integer.parseInt(tfNumberOfYears.getText());
      double monthlyInterestRate = Double.parseDouble(tfAnnualInterestRate.getText()) / 1200;
      tfFutureValue.setText(String.format("$%.2f", (investmentAmount * Math.pow(1 + monthlyInterestRate, years * 12))));
   }
}