diff --git a/src/fakultaet/fakultaet.c b/src/fakultaet/fakultaet.c
new file mode 100644
index 0000000..b05b947
--- /dev/null
+++ b/src/fakultaet/fakultaet.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int fakultaet(int n) {
+	// Checking if the input is either zero or one
+	if (n == 0 || n == 1)
+		return 1;
+
+	// The result multiplies with i and i increases every turn until the loop ends
+	int result = 1;
+	for (int i = 2; i <= n; i++) {
+		result *= i;
+	}
+
+	return result;
+}
\ No newline at end of file
diff --git a/src/fakultaet/fakultaet.h b/src/fakultaet/fakultaet.h
new file mode 100644
index 0000000..c2d4a62
--- /dev/null
+++ b/src/fakultaet/fakultaet.h
@@ -0,0 +1,6 @@
+#ifndef FAKULTAET_H
+#define FAKULTAET_H
+
+int fakultaet(int n);
+
+#endif
\ No newline at end of file
diff --git a/src/fakultaet/main.c b/src/fakultaet/main.c
new file mode 100644
index 0000000..d0ca0fe
--- /dev/null
+++ b/src/fakultaet/main.c
@@ -0,0 +1,19 @@
+#include "fakultaet.h"
+#include "../userinput.h"
+#include <stdio.h>
+
+int main() {
+	// minInput is set to 0 so there won't be any negative numbers
+	int minInput = 0;
+	// maxInput is set to 12 because 13 would be too big for int
+	int maxInput = 12;
+
+	int number = usergetd("Enter a positive number below 13: "), minInput, maxInput);
+
+	int result = fakultaet(number);
+	// result now has the factorial of the user input
+
+	printf("The factorial of %d is: %d\n", number, result);
+
+	return 0;
+}
\ No newline at end of file
diff --git a/test/fakultaet/test_fakultaet.c b/test/fakultaet/test_fakultaet.c
new file mode 100644
index 0000000..4414b23
--- /dev/null
+++ b/test/fakultaet/test_fakultaet.c
@@ -0,0 +1,20 @@
+#include "unity.h"
+#include "fakultaet.h"
+
+void setUp(){}
+void tearDown(){}
+
+// Test for the input zero
+void test_fakultaetOf0() {
+	TEST_ASSERT_EQUAL_INT(1, fakultaet(0));
+}
+
+// Test for the input one
+void test_fakultaetOf1() {
+	TEST_ASSERT_EQUAL_INT(1, fakultaet(1));
+}
+
+// Test for the input five
+void test_fakultaetOf5() {
+	TEST_ASSERT_EQUAL_INT(120, fakultaet(5));
+}
\ No newline at end of file