diff --git a/src/temperatur.h b/src/temperatur.h
index 1409e5d..ebdea50 100644
--- a/src/temperatur.h
+++ b/src/temperatur.h
@@ -7,4 +7,6 @@ float CzuK(float tempC);
 float FzuC(float tempF);
 float FzuK(float tempF);
 
+float KzuC(float tempK);
+
 #endif //TEMPERATUR_H
diff --git a/test/test_temperatur.c b/test/test_temperatur.c
index f237aaf..e27c7da 100644
--- a/test/test_temperatur.c
+++ b/test/test_temperatur.c
@@ -39,4 +39,11 @@ 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);
+}
 #endif