diff --git a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcController.java b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcController.java
index dddea79..12524fe 100644
--- a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcController.java
+++ b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcController.java
@@ -37,7 +37,11 @@ public class MatrixCalcController {
 
             String stringMatrixA = matrixATextArea.getText();
             String stringMatrixB = matrixBTextArea.getText();
-            if (util.checkInput(stringMatrixA) && util.checkInput(stringMatrixB)) {
+            try {
+                
+            } catch (Exception e) {
+                //TODO: handle exception
+            }
 
                 double[][] matrixA = util.stringToMatrix(stringMatrixA);
                 double[][] matrixB = util.stringToMatrix(stringMatrixB);
@@ -47,7 +51,6 @@ public class MatrixCalcController {
 
                 outputText.setText(DisplayableString);
                 outputText.setTextAlignment(TextAlignment.CENTER);
-            }
             // System.out.println(matrixATextArea.getText());
         });
 
@@ -56,7 +59,11 @@ public class MatrixCalcController {
             MatrixCalcIOUtils util = new MatrixCalcIOUtils();
 
             String stringMatrixA = matrixATextArea.getText();
-            if (util.checkInput(stringMatrixA)) {
+            try {
+                
+            } catch (Exception e) {
+                //TODO: handle exception
+            }
 
                 double[][] matrixA = util.stringToMatrix(stringMatrixA);
                 double[][] result = math.matrixTransponation(matrixA);
@@ -65,7 +72,6 @@ public class MatrixCalcController {
 
                 outputText.setText(DisplayableString);
                 outputText.setTextAlignment(TextAlignment.CENTER);
-            }
         });
 
         addButton.setOnMouseClicked((event) -> {
@@ -74,7 +80,11 @@ public class MatrixCalcController {
 
             String stringMatrixA = matrixATextArea.getText();
             String stringMatrixB = matrixBTextArea.getText();
-            if (util.checkInput(stringMatrixA) && util.checkInput(stringMatrixB)) {
+            try {
+                
+            } catch (Exception e) {
+                //TODO: handle exception
+            }
 
                 double[][] matrixA = util.stringToMatrix(stringMatrixA);
                 double[][] matrixB = util.stringToMatrix(stringMatrixB);
@@ -84,7 +94,6 @@ public class MatrixCalcController {
 
                 outputText.setText(DisplayableString);
                 outputText.setTextAlignment(TextAlignment.CENTER);
-            }
         });
 
         substractButton.setOnMouseClicked((event) -> {
@@ -94,13 +103,9 @@ public class MatrixCalcController {
             String stringMatrixA = matrixATextArea.getText();
             String stringMatrixB = matrixBTextArea.getText();
 
-            boolean stop = false;
-
             try {
                 util.checkInput(stringMatrixA);
             } catch (Exception e) {
-                stop = true;
-
                 outputText.setText(e.getMessage() + "A");
                 outputText.setTextAlignment(TextAlignment.CENTER);
             }
@@ -108,14 +113,10 @@ public class MatrixCalcController {
             try {
                 util.checkInput(stringMatrixB);
             } catch (Exception e) {
-                stop = true;
-
                 outputText.setText(e.getMessage() + "B");
                 outputText.setTextAlignment(TextAlignment.CENTER);
             }
 
-            if (util.checkInput(stringMatrixA) && util.checkInput(stringMatrixB) && !stop) {
-
                 double[][] matrixA = util.stringToMatrix(stringMatrixA);
                 double[][] matrixB = util.stringToMatrix(stringMatrixB);
 
@@ -131,10 +132,6 @@ public class MatrixCalcController {
                     outputText.setText(e.getMessage());
                     outputText.setTextAlignment(TextAlignment.CENTER);
                 }
-                
-
-
-            }
         });
 
         DetAButton.setOnMouseClicked((event) -> {
@@ -143,18 +140,14 @@ public class MatrixCalcController {
 
             String stringMatrixA = matrixATextArea.getText();
 
-            boolean stop = false;
             try {
 
                 util.checkInput(stringMatrixA);
 
             } catch (IllegalArgumentException e) {
-                stop = true;
-
                 outputText.setText(e.getMessage());
                 outputText.setTextAlignment(TextAlignment.CENTER);
             }
-            if (util.checkInput(stringMatrixA) && !stop) {
 
                 double[][] matrixA = util.stringToMatrix(stringMatrixA);
                 try {
@@ -170,7 +163,6 @@ public class MatrixCalcController {
                     outputText.setText(e.getMessage());
                     outputText.setTextAlignment(TextAlignment.CENTER);
                 }
-            }
         });
 
         DetBButton.setOnMouseClicked((event) -> {
@@ -178,18 +170,14 @@ public class MatrixCalcController {
             MatrixCalcIOUtils util = new MatrixCalcIOUtils();
 
             String stringMatrixB = matrixBTextArea.getText();
-            boolean stop = false;
             try {
 
                 util.checkInput(stringMatrixB);
 
             } catch (IllegalArgumentException e) {
-                stop = true;
-
                 outputText.setText(e.getMessage());
                 outputText.setTextAlignment(TextAlignment.CENTER);
             }
-            if (util.checkInput(stringMatrixB) && !stop) {
 
                 double[][] matrixB = util.stringToMatrix(stringMatrixB);
                 try {
@@ -205,7 +193,6 @@ public class MatrixCalcController {
                     outputText.setText(e.getMessage());
                     outputText.setTextAlignment(TextAlignment.CENTER);
                 }
-            }
         });
     }
 }
\ No newline at end of file
diff --git a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcIOUtils.java b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcIOUtils.java
index ab3ab7e..20c5130 100644
--- a/src/main/java/com/ugsbo/matrixcalc/MatrixCalcIOUtils.java
+++ b/src/main/java/com/ugsbo/matrixcalc/MatrixCalcIOUtils.java
@@ -42,8 +42,7 @@ public class MatrixCalcIOUtils {
      * @param matrix It is the InputMatrix
      * @return true if the Matrix is valid Input.
      */
-    protected boolean checkInput(String matrix) throws IllegalArgumentException {
-        boolean isMatched = false;
+    protected void checkInput(String matrix) throws IllegalArgumentException {
         if (matrix.length() == 0) {
             throw new IllegalArgumentException("Please insert a Matrix");
         }
@@ -59,13 +58,10 @@ public class MatrixCalcIOUtils {
 
         Pattern p = Pattern.compile(row1 + row2 + row3);
         Matcher m = p.matcher(matrix);
-
-        isMatched = m.matches();
-        // TODO change the funktion to void and just throw exceptions if something went
-        // worng
-
-        // System.out.println(isMatched);
-        return isMatched;
+        
+        if(!m.matches()){
+            throw new IllegalArgumentException("A Matrix is not in the right format, Matrix ");
+        }
     }
 
     /**
diff --git a/src/test/java/com/ugsbo/matrixcalc/MatrixIOUtilsTest.java b/src/test/java/com/ugsbo/matrixcalc/MatrixIOUtilsTest.java
index b01e775..6f501f7 100644
--- a/src/test/java/com/ugsbo/matrixcalc/MatrixIOUtilsTest.java
+++ b/src/test/java/com/ugsbo/matrixcalc/MatrixIOUtilsTest.java
@@ -2,6 +2,7 @@ package com.ugsbo.matrixcalc;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import org.junit.Before;
@@ -30,27 +31,45 @@ public class MatrixIOUtilsTest {
     public void checkIfA1by3MatrixIsValidInput() {
         String input = "1 2 3";
 
-        boolean result = util.checkInput(input);
+        try {
+            // act
+            util.checkInput(input);
 
-        assertTrue("The 1 by 3 Matrix should be Matched as valid input.", result);
+            // assert
+            assertTrue("The 1 by 3 Matrix should be Matched as valid input.", true);
+        } catch (IllegalArgumentException e) {
+            assertFalse("The 1 by 3 Matrix should be Matched as valid input.", true);
+        }
     }
 
     @Test
     public void checkIfA2by3MatrixIsValidInput() {
+        // arrange
         String input = "1 2 3\n1 2 3";
 
-        boolean result = util.checkInput(input);
+        try {
+            // act
+            util.checkInput(input);
 
-        assertTrue("The 2 by 3 Matrix should be Matched as valid input.", result);
+            // assert
+            assertTrue("The 2 by 3 Matrix should be Matched as valid input.", true);
+        } catch (IllegalArgumentException e) {
+            assertFalse("The 2 by 3 Matrix should be Matched as valid input.", true);
+        }
     }
 
     @Test
     public void checkIfA3by3MatrixIsValidInput() {
         String input = "1 2 3\n1 2 3\n1 2 3";
 
-        boolean result = util.checkInput(input);
+        try {
+            util.checkInput(input);
+
+            assertTrue("The 3 by 3 Matrix should be Matched as valid input.", true);
+        } catch (IllegalArgumentException e) {
+            assertFalse("The 3 by 3 Matrix should be Matched as valid input.", true);
+        }
 
-        assertTrue("The 3 by 3 Matrix should be Matched as valid input.", result);
     }
 
     @Test