diff --git a/src/temperatur.c b/src/temperatur.c
new file mode 100644
index 0000000..7c6929e
--- /dev/null
+++ b/src/temperatur.c
@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <string.h>
+#include "temperatur.h"
+
+float CzuF(float tempC){
+	return (tempC * 9/5) + 32;
+}
+float CzuK(float tempC){
+	return tempC + 273.15;
+}
+
+float FzuC(float tempF){
+	return (tempF - 32) * 5/9;
+}
+float FzuK(float tempF){
+	return (tempF - 32) * 5/9 + 273.15;
+}
+
+float KzuC(float tempK){
+	float tmp = tempK - 273.15;
+	//Variable auf 2 Nachkommastellen begrenzen
+	return ((int)(tmp * 100 + 0.5) / 100.0);
+}
+float KzuF(float tempK){
+	float tmp = (tempK - 273.15) * 9/5 + 32;
+	//Variable auf 2 Nachkommastellen begrenzen
+	return ((int)(tmp * 100 + .5) / 100.0);
+}
+
+const char* getFirstUnit(int input){
+	if(input < 3)
+		return "Celsius";
+	else if(input < 5)
+		return "Fahrenheit";
+	else if(input < 7)
+		return "Kelvin";
+	return "";
+}
+const char* getSecondUnit(int input){
+	 if(input == 1 || input == 6)
+		 return "° Fahrenheit";
+	 else if(input == 2 || input == 4)
+		 return " Kelvin";
+	 else if(input == 3 || input == 5)
+		 return "° Celsius";
+
+
+	return "";
+}
+
+int run_TemperaturRechner(){
+		float var1, var2;
+		int var3;
+		
+		printf("\nTemperaturkonverter (Celsius, Fahrenheit, Kelvin)\nAchten Sie darauf, Kommazahlen mit einem Punkt anzugeben!\n\n");
+
+		while(1){		
+			printf("Waehlen Sie: \n<1> Celsius zu Fahrenheit\n<2> Celsius zu Kelvin\n<3> Fahrenheit zu Celsius\n<4> Fahrenheit zu Kelvin\n<5> Kelvin zu Celsius\n<6> Kelvin zu Fahrenheit\n<7> Zum beenden\nAuswahl: ");
+			scanf("%d", &var3);
+			
+			if(var3 < 1 || var3 > 7){
+				printf("Eingabe nicht zulaessig!");
+				break;
+			}
+			else if(var3 == 7)
+				break;
+			
+			printf("\nGeben Sie die Temperatur in %s ein: ", getFirstUnit(var3));
+			scanf("%f", &var1);
+			
+			
+			switch(var3){
+				case 1:
+					var2 = CzuF(var1);
+					break;
+				case 2:
+					var2 = CzuK(var1);
+					break;
+				case 3:
+					var2 = FzuC(var1);
+					break;
+				case 4:
+					var2 = FzuK(var1);
+					break;
+				case 5:
+					var2 = KzuC(var1);
+					break;
+				case 6:
+					var2 = KzuF(var1);
+					break;
+			}
+			
+			printf(" = %.2f%s\n\n", var2, getSecondUnit(var3));
+			
+		}
+
+	return 0;
+}
diff --git a/src/temperatur.h b/src/temperatur.h
new file mode 100644
index 0000000..010365b
--- /dev/null
+++ b/src/temperatur.h
@@ -0,0 +1,15 @@
+#ifndef TEMPERATUR_H
+#define TEMPERATUR_H
+
+float CzuF(float tempC);
+float CzuK(float tempC);
+
+float FzuC(float tempF);
+float FzuK(float tempF);
+
+float KzuC(float tempK);
+float KzuF(float tempK);
+
+const char* getFirstUnit(int input);
+const char* getSecondUnit(int input);
+#endif //TEMPERATUR_H
diff --git a/test/test_temperatur.c b/test/test_temperatur.c
new file mode 100644
index 0000000..04485a8
--- /dev/null
+++ b/test/test_temperatur.c
@@ -0,0 +1,68 @@
+#ifdef TEST
+
+#include "unity.h"
+
+#include "temperatur.h"
+
+void setUp(void)
+{
+}
+
+void tearDown(void)
+{
+}
+
+void test_temperaturRechner_CzuF(void)
+{
+float result = CzuF(25);
+float expected = 77;
+TEST_ASSERT_EQUAL(expected, result);
+}
+
+void test_temperaturRechner_CzuK(void)
+{
+float result = CzuK(25);
+float expected = 298.15;
+TEST_ASSERT_EQUAL(expected, result);
+}
+
+
+void test_temperaturRechner_FzuC(void)
+{
+float result = FzuC(77);
+float expected = 25;
+TEST_ASSERT_EQUAL(expected, result);
+}
+void test_temperaturRechner_FzuK(void)
+{
+float result = FzuK(77);
+float expected = 298.15;
+TEST_ASSERT_EQUAL(expected, result);
+}
+
+void test_temperaturRechner_KzuC(void)
+{
+float result = KzuC(298.15);
+float expected = 25;
+TEST_ASSERT_EQUAL(expected, result);
+}
+void test_temperaturRechner_KzuF(void)
+{
+float result = KzuF(298.15);
+float expected = 77;
+TEST_ASSERT_EQUAL(expected, result);
+}
+
+void test_returnUnit_first(void)
+{
+const char *result = getFirstUnit(1);
+char expected[] = "Celsius";
+TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+void test_returnUnit_second(void)
+{
+const char *result = getSecondUnit(2);
+char expected[] = " Kelvin";
+TEST_ASSERT_EQUAL_STRING(expected, result);
+}
+#endif